I'd also like to know about the EVO carts, I'm a newbie and I love my M403, which I bought because it's small, but even after trying a few mods (I'm using a PTB mod at present), I still find that I'm refilling the cart several times a day. If I could knock that down to just a couple, I'd be much happier. I don't even come close to refilling near as much on my 510.
BTW - I just got the M402 Smart PCC from Sharp Smoker and this thing rocks! It's obviously easier to use with a 402 battery, but my 403
batteries still fit quite well (it's also notched for manual batteries to fit. If you have fat fingers, it's gong to be a pain to screw and unscrew the battery from it's charging slot though. I still love this thing - it's very well constructed.