[Top Dog]

Exactly! WR1 is within reach of a ganger, but not rating 2, and neither is a top of the line cyberarm.
Though I disagree about the Essence thing... there is a mechanic built into the system that reflects how people react negatively to low Essence characters, it's part of the calculation for Social Limits. People are going to react differently to you depending on how much 'ware you have, because that matters even in 2072. And some people are going to be aware of that, and that is going to influence their decision to get an arm or not, most people probably. So there is likely to be at least some small social stigma attached to major implants. Plenty enough reason to justify paying a little more for a synthetic arm.

Essence tying into social limit doesnt have much to do with social stigma. Instead, its a result from a sort of reversed uncanny valley effect, the idea that humans are instinctively put off by things that look uncannily like humans but arent (robots and such). Social stigma comes on top of that, depending on the crowd, in the form of negatie dice mods (or positive, ynever know).

I've always read the essence tying into limit part as an internal thing. As you replace yourself with mechanical parts, you become less human; your link towards the rest of the human race diminishes, you become colder and less empathetic. It's a central theme in a lot of cyberpunk.

After all, the lower social limit also applies in cases where the opposing party could never even get a visual hint that you're wearing cybernetics (wired reflexes that are off, or an audio only link). It's your behavior that's affected, not the other party's response to it.

Which, I guess, is why synthetic and obvious limbs have the same essence cost; you're still replacing your limb with a piece of machinery (although an argument could be made that, by choosing the one that looks more human, you're less removed from being human).

[Anarkitty]

No matter how human a cyberlimb might look, to the piece of your soul that left with your flesh and blood arm it is the same as grafting a small backhoe shovel to your shoulder, or just leaving it off entirely.  Hence the same essence cost.
I agree that the Essence affecting your Social limit is a change in you, not the person you're talking to.  When you lose a part of your soul, it makes you less human, and less able to understand and interact with other humans.  It is very clearly stated in multiple editions that characters with very low Essence start to feel "detached" from their humanity and others, and even before they cross the line into cyber-zombie territory they risk disassociative disorders and cyber-psychosis.  Sometimes there are rules for this, sometimes there aren't, but it's part of the setting.
That is why the effect on your Social limit is the same whether your essence loss is from internal cyber, bio, or chrome limbs, and whether you are talking to a mage, a sammie or an AI.  It represents a disassociation with your own self.

Obvious cyberlimbs never get explained in much more detail than being "obvious". Ergo, it's natural everyone has their own opinion on how they should look, even the artists who make SR art themselves
Personally, I think they just look like normal limbs in silhouette, but obviously (heh) mechanical somehow. Think John Kennox from Almost Human, or even the automail from Fullmetal Alchemist. Anything more substantial than that would most likely be a bulk-upgraded limb, and prove somewhat impractical.

A synthetic cyberlimb has a set appearance.  It looks like an arm.  Probably like your arm, unless you bought it used, or got a sun tan since you picked it up.
An obvious limb  doesn't have a set appearance.  It is "obvious", which can range anywhere from a cheap model with skin-tone plastic shell and visible bolts and interface ports, a hyper-realistic arm that happens to be polished chrome, a steel and titanium frame with myomer wire bundles and pistons visible between the ceramic armor plates, or even a detailed work of art or engineering that doesn't even resemble the limb it is replacing.  It can look like anything, as long as that appearance can be justified relative to the stats in the same. 
If you have an arm that is AGI 10, it could be a smooth, precision-machined piece that looks like an impossibly lithe, chrome version of your real arm; or it could be a triple-jointed marvel of engineering that can move and bend in ways no metahuman limb ever could; or a hand-crafted work of art that twists and flows like a tentacle with a gleaming, multicolored surface of independently moving ceramic scales.  As far as the actual effect in the game, all of these arms have the same cost and the same effectiveness.

It isn't about saying, "This is what obvious cyberlimbs look like." It is about saying, "I have this idea of what my cyberlimb looks like, should I consider that Obvious or Synthetic?"

[Insaniac99]

That was wonderfully put Anarkitty

[Lusis]

So if I imagine arms that are visibly slender and lithe (and dpnt use more that 8 capacity in extras), but are painted black, are they obvious or synthetic?

[The Wyrm Ouroboros]

Probably obvious.  Unless your character is black.  The question you should answer is, 'if you shake hands with someone, is it going to be obvious that your hand/arm is cybernetic?'  Or 'if you're in your swimsuit, is it obvious' etc.  For the answer to be 'no', the cyberlimb should look just like you do.  If it's 'no', then there you go.

Or use the 10' rule - can a person standing 10' away tell that the uncovered limb is artificial?  However you describe it looking, the answer would have to be 'yes' for it to be an obvious cyberlimb.

[Lusis]

But still no concealability modifier in clothing, which would be conceivable in this case.  Now this could be handled by a bonus to a disguise test to hide under clothing, or some math inversely relating concealability and used capacity.

It's kind of all moot though because any professional geardo is going to use a scanner on everyone he meets.

[The Wyrm Ouroboros]

That's up to the player and the GM, as to how blatant they want the 'ware to be.  If you want it to be a huge blatantly-mechanical piece that can't even be put through a normal sleeve, that's up to you, but in regards to the rules, it's still 'just' an obvious cyberlimb.

And any professional 'geardo' that tries to use a scanner on any of my characters had better be holding them at gunpoint.  Even then, his life isn't guaranteed safe, because some of them aren't going to stand for it no matter what.

[Lusis]

Would you even notice if someone used a cyberware scanner on you considering it has a 15 meter range? I wouldn't think it gives any indication. I also assume that everyone is subject to all kinds of sensors, without their knowledge,  in the more reputable parts of civilization.

[The Wyrm Ouroboros]

(Note that the table has a few errors in it - the more items you have, the LOWER the threshold should be, not higher.  Anyhow.)

Remember that 15m is the maximum range; also, it would/should take both a clear line to the target and at least a couple of Turns for the gizmo to do its job.  And it is a gizmo, make no mistake; at the very least, think of the ultrasound motion detectors from Aliens.  It is, or should be, clear that someone is pointing something at you.  Plus, anyone who has something that can perceive millimeter-wave radar (i.e. another one, or even just a radar detector of some sort) is gonna notice that sort of thing scanning around.  Sensors don't operate in a void; there's always counterdetection and concealment to consider.

But yeah, I think a reasonably-aware shadowrunner would have a decent chance to notice someone using a scanner on them.  It is, after all, a max of 15m, and the closer you are, the more sure you are of actually scanning the right target.

[Lusis]

A couple of problems with your points. First, the book does not give a threshold "of a couple of turns"; it's pretty instant. Second, there's no whirring devices here or Star Trek scanning beams that I've read about, unless it's in an older sourcebook. So it'd realistically be a regular perception (or electronic warfare) test with a reasonably high threshold to detect what you were being scanned with, even if it was a guard with a handheld scanner, much less an inconspicuous sensor array on a building or in someone's helmet/ballistic mask.

[The Wyrm Ouroboros]

First, if you're right next to the guy, sure, 'pretty instant' I'll grant you.  The book doesn't give every single last detail, though, so don't stay slavishly devoted to 'what the book says'.  You still have to be sure you're targeting the right person if there's a crowd, and there is a question of range, detail, etc.  No, you don't have to play it that way.

Second, I didn't mention whirring devices or scanning beams, but if it emits energy, it can be detected.  A standard perception test to notice the guy pointing the gizmo at you, sure.  An e-war test to detect directed-energy scanning, sure.  A reasonably high threshold?  Oh, hell no, not when the scanner is sending out energy.  Passive is tough/impossible to detect, but to know that you're being scanned is a one-hit threshold.  Perhaps to deduce where it's coming from, yeah, that might be tougher if the scanner is concealed in some way - or it might be idiot-simple, such as if you're approaching a guard post and a guy with a helmet/face-mask is looking your way, or if you just passed through a doorway.

The book isn't the be-all and end-all; use a big dose of your own experience when judging this sort of thing.

[Novocrane]

Note that the table has a few errors in it - the more items you have, the LOWER the threshold should be, not higher.  Anyhow

Line that up with the relevant fluff, and you should notice that SR5 gets right. Millimetre Wave scanners do have issues with lots of items and packed electronics on screen - both in SR and modern day. You can either research this yourself, read Runner's Companion, or think back to the last time airport security asked you to remove your laptop or other large electronic device from it's bag for scanning.

[Lusis]

Eh...but these are people you are playing with and it'd be kinda de-immersing imo to just throw that little roadblock out based on "experience" that amounts to an assumption, when current technology, such as airport body scanners, while considerably bulkier than SR tech, have no such effects. 

The way I would GM is based on context.  If it was a person with a handheld,  yeah you'll know, and you can roll E-war skill or an appropriate knowledge skill to figure out what with;  but in the case of inconspicuous scanners, very unlikely, depending on the situation.  You aren't going to have mysterious sensor-energy detection abilities by default.

Just my opinion.

[The Wyrm Ouroboros]

Line that up with the relevant fluff, and you should notice that SR5 gets right. Millimetre Wave scanners do have issues with lots of items and packed electronics on screen - both in SR and modern day. You can either research this yourself, read Runner's Companion, or think back to the last time airport security asked you to remove your laptop or other large electronic device from it's bag for scanning.

Ooo, so it gets confused by multiple returns - definitely becomes useless against someone who does have multiple implants.  Fun fun.