Right now i'm using my first PV, a NicStick (510 style i bought at a local gas station), but i'm looking into upgrading to something with longer battery life and better vaping. I've decided to try the eGo, heard lots of good things about it. I'm going to get it from myfreedomsmokes, just gonna buy the battery, atomizer, and carts separately and put it together, don't want to spend the $ on a starter kit. I've ordered some Newport juice and a case from them recently and i'm pretty happy with their service and prices, but i see that they offer three models, the regular eGo, the eGo Mega, and the eGo-T. Whats the difference between them? Besides the parts not being interchangeable.