I find Manablade and Powerblade to be pretty straightforward.
Magic + Spellcasting (no specialization because it's a weird thing, but if I had to classify, it's Manipulation) - if you get any net hits, you have a blade of the given type that is statted out thusly:
Manablade:
[Force]P damage
[Force] Accuracy
Reach 1
You can attack with your Manablade with Clubs or Blades and it deals higher damage as normal for net hits. It can only be parried by powerblades, manablades or weapon foci. It's damage is resisted by Willpower alone.
Powerblade:
[Force]P damage
[Force] Accuracy
Reach 1
You can attack with your Powerblade with Clubs or Blades and it deals higher damage as normal for net hits. It can be parried by anything and armor is used to resist it.
That said, I agree with
Jack_Spade here:
Yeah, one is meant to be a direct mana spell and the other an indirect one with AP equal to force. At least that is what the description infers.
I believe that Powerblade is supposed to also have -Force AP. They just used Powerblade where they should have used Punchblade/Cloutblade/Blastblade instead. Personally, I'd also drop the drain value on the Powerblade down to F-4 because it's worse in most ways. And I'd add Lightningblade, Fireblade, Acidblade, Iceblade, Radiationblade, Pollutionblade, and Sunblade as options, with differing drain codes.
The Elemental Blade spells would then mostly be F-2 (like Manablade) because you'd also get the elemental effect. I could be argued into having Waterblade at F-3 as well, because it makes me laugh so much. And I'd allow an Adept Spell version that only allows you to cast it through a sustaining focus, but you get all the X-Blades you want to buy at 5 karma apiece. The power only comes with one though.