My lone Pico got a weeks worth of use before getting tossed in the stash. Not a big fan of how it feels in my hand and the single cell battery life with even toodle puffing builds was unexceptable.
Oddly I found the Pico-Mega more to my liking. The size and shape plus the 26650 battery life put it on par with my other 26650 mods I have. I liked it so much I purchased 2x more of them for the stash.
Funny, since I have USB charging at my desk at work a single 18650
mod can serve as "drive duty". A Evic VTC Mini has been filling that role for sometime now. Fairly small and light (with Lemo2 mounted) the combo works without any 510 issues.
For REALLY SMALL and LIGHT I've gone with the Target Mini with a OBS Crius mounted. It will only last a few hours on a charge but with USB charging nearly everywhere the lack of size and weight (and the dual coil atomizer!) make it a very pocketable cloud producing little power house.
I've resigned to having single 18650 and smaller mAH mods as novelty items and purchase ether 26650 mods or 2x18650 mods (for the dual coil setups) so I don't feel like I'm always swapping mods for one that has a charge on it. Last summer I took a 2x26650 mod on a weekend camping trip and did not have to swap
batteries. (the ultimate in battery run time)
I would not be surprised if the Pico was
eleaf's #1 selling mod. They seem to just keep coming out with new colors!