I started vaping on a 510, then the 510 tank and I got sick of charging and changing batteries all the time. I ordered the eGo T and love it! I ordered one in pink (of course) and one in blue so I'd have a back-up. It really smokes great and the tank holds a good amount of juice.
It was nice at work today, not having to change my battery at all! I started vaping this morning at 5am and it's now 10:30pm and the battery is still going strong!
For those looking to move to something a little bigger than the 510 - I recommend the eGo!
Just wanted to share my experience.