The eGo is a solid performer, and I always say that every vaper should have at least one eGo kit in their collection.
The eGo is essentially the same thing as a Joye 510, just with a larger battery for longer vape time. However, they're really good, solid E-cigs. I have 8 eGo batteries myself and still use them -- the first ones I bought over a year ago are still going strong.
Almost every vendor sells an eGo kit of some stripe. My recommendation is to go with a standard eGo kit (not the eGo-T tank system; a lot of people love them but I just couldn't bring myself to, as there were too many major flaws for me) and buy yourself some Boge low resistance cartomizers to go with them. Couple that with
juice from a decent vendor and you have yourself an excellent
vaping setup that'll blow any gas station/mall kiosk type E-cig away.
Now, if you want something that looks and feels more like a traditional cigarette (which is important to some people) I would go for something like the Smokeless Image Volt, Bloog MaxxFusion or Smoov E-cigs. They're slim, battery life is still pretty good (not as good as the eGo, naturally) and they're great performers as well. However, just keep in mind that these have different connectors than the eGo. The eGo uses a 510 connector (the most common type), while the Volt, Bloog and Smoov are all based on the KR808D-1 (a.k.a. 808) connection, so you need to make sure the cartomizers you buy match your battery connector.