I would say swisstool but I've only tried the Charge once in a shop, and never tried the powerlock.
for the clip, be sure to try it before buying (if you buy the multitool because of that feature), I've read somewhere that it's not very good.
for the one handed opening, I would say that neither the Charge nor the swisstool are "flip-opening" friendly, but you can for sure open them with one hand, it just takes more time