This is fairly open ended question so this is going to be long. First off, you have to be familiar with how cyberlimbs and their attributes work. Tooting my own horn,
here's my explanation on how that works. Some of the following debate does require GM arbitration since some guidelines are vague as all hell. However, I'm going with stuff that is quite reasonable to infer and suggested by the writing so I don't think what I'm saying is too outlandish. But it's a disclaimer nonetheless.
Assuming you understand how cyberlimb attributes work, the reason why cyberlimbs are so good is that that they are cheap attribute boosts. Since they are derived wholly independent of your current attributes, you can get away with fairly low attributes and use the points elsewhere.
For example, let's say you're a 4 Body 2 Strength 2 Agility starting Human runner. At creation, you get the following cyberlimb, Obvious Customized Right Cyberlimb Avail: 12 27000Y Body: 6 Strength: 5 Agility: 6
With that, you also buy Body Enhancement 3 600Y Armor 2 600Y Agility Enhancement 3 600Y
The final attributes of the limb are Body 6(9) Strength 5 Agility: 6(9).
With this new arm, you go down to the range and get a smartlinked pistol and use it one-handed. Let's say you have Pistols 4 as well.
With a normal meat arm, you'll be rolling 8 dice (Agility 2 + Pistols 4 + Smartgun 2).
With your cyberarm, you're rolling 15 dice (Agility 9 + Pistols 4 + Smartgun 2). A seven dice difference!
You can one-hand firearms up to SMGs in size. Depending on your GM for two-handed weapons, you likely roll 5 dice (if your two arms average) or you stay at 2 (if this requires careful coordination). I prefer the former averaging choice, but you have argument either way. If you're using Strength grants RC, you might want Strength Enhancement 1 to get 6 Strength and +1 RC.
Due to the averaging for whole body tests such as damage, you get to roll 5 dice from body instead of the normal 4. The math is (Right Arm 9 + Left Arm 4 + Torso 4 + Right Leg 4 + Left Leg 4) / 5 = 25/5 = 5. Umaro has this averaged body count towards armor encumbrance which I think is reasonable (wearing stuff usually doesn't require careful coordination) so I will be factoring that in as well.
Therefore, you now roll 5 dice for Body instead of 4 as well being able to wear 2 extra points of armor due to higher encumbrance limit. In addition to this, you get 2 points of armor that stacks with everything and doesn't count towards encumbrance (remember encumbrance only applies to worn armor not innate armor). This means you roll 5 extra dice to resist damage.
In addition to this, you get some other minor beanies like +1 physical damage track and 3P punches. The arm I provided also has 5 capacity left over for you to add stuff. I like cyberarm gyromounts personally, but they're F so you might want to avoid them.
So for 28600Y at character creation, you get +7 dice for shooting people, +5 dice to resist damage, and a host of minor beanies. It's a pretty good deal. Basically you
peel, lick and stick a cyberlimb onto a character to make them in decent combat character.
