I got a SMPL and derringer (clone) a few days ago, after salivating for one for a few months.
I cant believe the flavor and clouds that come out of it. It really gives everything else I have a run for its money. The clouds are impressive for such a tiny RDA, must be the density that does it. The flavor seems to be a touch better then everything else i have, cleaner and more robust.
I do think the safety awareness has to be ramped up for it, since it uses the battery casing for an insulator, so I check my bats casing insulator compulsively. And the 510 must stick out (NO Pro Tanks, LOL). I polished up the bottom of the button where it hits the battery with a felt wheel and polish compound, but other than that it was good out of the box.
The Derringer was as easy as build, wick, drip and vape. 26 g @ .3 ohm. I really thought it would vape too hot, but its fine as long as it has juice on it.
Ran my bat down to 3.5 today cause it was just running so darn good, :?)