I just got my first T3 and an eGo Twist to power it; I'm a refugee from Smokeless Image and the Land of Leaky CE3s. (though i do suspect they will rectify the situation with new hardware very shortly and I'll happily give that stuff a try too)
Anyway, I'm pretty dang happy with the T3. The variable voltage thing isn't just a gimmick, it really DOES make a difference not only in battery life but in how some juices taste. I've had a few that were just plain HARSH even when the CE3s were working fine, and could only vape those in regular cartos. Using the same juice in the T3, if I just back the voltage down to about 4, I get lots of flavor and vapor and none of the harshness. btw, I guess I should mention that I define harshness as a REALLY heavy throat hit and a burning sensation on my tongue.
(edit: just realized that the majority of this paragraph is about the Twist and not the T3...)
Anyway, I'm diggin' my new setup. I was content to stick with SI's Volt X2 and CE3s until the manufacturing on the CE3s when haywire.