Body Mastery
Conserve Power (Nice for longer fights if you're not /regen)
Focussed Accuracy (OMGWTFBBW!!111!!)
Laser Beam Eyes (Meh damage, but at least it's not smashing/lethal)
Energy Torrent (Scranker cone-knockdown goodness)
Weapon Mastery
Caltrops (Makes mobs run, twice the recharge time of the blaster version)
Web Grenade (Handy for stopping fliers and runners)
Shuriken (Meh damage and it's lethal)
Exploding Shuriken (Fun at parties, but not much damage)
Darkness Mastery
Torrent (Knockback on a scrapper. Yuck!)
Petrifying Gaze (A hold, yay! Doesn't stack so can't hold bosses)
Dark Blast (Much the same as Energy Eyes but with a longer range)
Tenebrous Tentacles (Rahh!! All must feel the fury of my tenties of DOOOOM!!)
I went Body Mastery for PvE. Usually Dark's the big PvE one, with Weapon Mastery only really used for PvP Duelling. WM powers cause a lot of redraw animations so they tend to slow your damage output down.
finally almost got my MA/regen scrapper to level 41 and want some info on Weapon Mastery as i can't find any guides about it.
i know most go body mastery but i don't PvP much and for concept reasons like the look of this set but i know very little about it