I know allot of ppl say stack the crit in turn you lose pwr, well from my experience that extra 10% to crit (from 30 to 40) isnt worth the extra dps you will gain from Pwr, crits hit much harded when the proc when your dmg is much higher, and going over data over several months i dnt find I crit any less with the 30% then with the 40% this is what I have full buff:
Exper: 1199
pwr: 1084
cunn:1997
surge: 77.94
crit 29.97%
i'm still a few pieces from Min/Max so my stats will change slightly, now I'm one of the best scrapper scoundrels my server and can 1v1 any other class in game. I wish there was a way to stack pwr and crit on the same enhancments but there isnt so pwr is it for me... but we all have our own opinions and our own experiences... take the info given in these post and make your own decision and just try it out, in the end its not always bout haveing the better stat than the guy your fighting... sometimes it comes down to how good YOU are...