i say as long as you're not getting a blu/green/envy, etc.. then you're on the right path. most people go for the skinnier ecigs thinking that there's a mental connection between the physical size of the device and its probability to succeed, but there really isn't, i got over the ego's size in 2 seconds, it's all about how it feels when you inhale and exhale, and a 510 has it where it counts, but take a good look at the ego before you make your decision.
Jon