Not sure I have much original to say, but my experience after 30 days using the eGo-T, it being my first vaping experience and device, is that its more a matter of learning how best to use it. When I first got it, I was keeping the button pressed too long, and taking a single draw. I ruined two type A attys in about 20 days. I've now switched to the type B and its a whole new experience. Much better in every respect. I now take a draw into my mouth, then a second into my lungs, before both exhale. Obviously the vape is just ridiculous. Looks like I'm vaping pure VG, though I believe I'm vaping pure PG. Very few very moderate leaks on the type A, and virtually nothing on the type B after 10 days. I also went with the silicone caps and they've been great. Much easier to remove, but very secure and perfectly tight in terms of keeping away leaks. Although I bought a type A atty when I bought two type B attys for the first time, after using the type B I packed up all my type A stuff. Type B is just far superior.
So, focusing back on the leaks, mine does rest horizontal for most of the time, mostly due to paranoia from other commenters in various threads saying leaving it standing vertical can cause leaks... but even before reading those comments and keeping the device standing when at rest, I wasn't experiencing leaks. I think this is a case of having a less-than-perfect tank/cap than any inherent device flaw.
I'm sure I'll progress at some point to a juice feeder, but for now the eGo-T has been my perfect solution. Those experiencing some frustrations... don't give up on it too easy.
Oh, as for cost... when the atty is working well for me, the cost to vape vs analogs is 1/12th. When I had to replace attys after just 10 days each, the comparitive cost rose to just 1/4. Still a win-win.
(I'm yet to try carto's... I'm still at a point of learning what I can and can't use with this device, in terms of all different fittings and resistances, etc. It looks to be getting more confusing each week as the market explodes)