I've fallen in love with Kanger Evods.
I've tried all kinds of CEs (CE2, CE4, CE4+, CE5), and while most of them don't leak too much, they all have a very tight draw, don't provide overly much flavor, and --this is the worst-- give a fair number of burnt hits. Using them on a lanyard virtually guarantees this.
I've also tried Joyetech's e-Go T tank system (as well as the new one with replaceable heads), and it's simply wretched -- never has a vaping device produced so little flavor. Plus, you have to reload the liquid all the time. And they often leak catastrophically.
I still use some Vivi Mini Novas with metal tanks for tank cracker juices, and they're actually pretty darned good. They provide a lot of flavor. You have to be very careful not to fill them more than about 65-70% of the way up, though, or you get a huge leak out the bottom every fscking time. But that's my only complaint (okay, they're pretty inelegant, too, but I don't really care about that.)
The Evods, though, boy are they nice! Excellent flavor, to start with. No dry hits ever, thanks to the bottom-feeding design. And with exactly two exceptions, I've never had one leak on me -- they do occasionally gurgle a bit, but since the head is so far down you don't end up with liquid in your mouth or anything. (The two exceptions were catastrophic failures -- full tanks leaked most of their contents into my shirt pocket. In once case, I later realized the tank was cracked due to a forbidden juice being in there, so really, it's down to one unexplained failure, and for all I know I didn't tighten something up after filling it.)