You probably already placed an order for something since this post isn't brand new, but here are my thoughts. I had a 510-T a long time ago (before I discovered VV mods), and I found that the tanks severely muted the flavor of my juices. It also made the vapor too cool, thus lowering throat hit, etc. But lately I've started missing the "holding a cigarette" feeling so I ordered an eRoll. Well, it arrived in the mail just today, and I totally love it. As others have said here, it is miles beyond the 510-T. The atomizers are better, and I don't know if the tanks are thinner, but they do not restrict much (if any) flavor or heat. It's almost like I'm vaping an Ego or something, yet since the battery is lighter and shorter than a 510 I can do it like an analog, or hands-free.
Plus, the PCC? It's awesome. You don't have to disassemble or screw in anything. You just take a few puffs, literally drop the eRoll into the slot, and throw it in your pocket. And the tanks can fit in a Tic Tac or small Altoids container. As a bonus, my roommates thought it was my iPhone for a minute which was hilarious.