Although I have several mods with internal batteries that aren't easily removable, I'm concentrating more on mods with replaceable batteries for longevity. I like the 75W Pico over my other USB iSticks and Innokins. The USB devices get used around the house more than when I'm away. For a day out and about I want to be able to swap out a battery and continue on.
Anyone bought the triple battery Pico 200W? That one may be good at low wattage just for the battery life. It resembles my Wismec Reauleaux RX200S.
The Pico 100W looks good for its ability to work at 75W or 100W with either 1 or 2 18650's. I'm one who likes long vaping time at low watts on multi-battery mods, especially if it's a stealthy profile mod.
I carry one of these Efest battery cases in my vehicle with an 18650 and a 15ml bottle of juice for backup, along with one of those keychain jeweler's screwdrivers in a zip lock so it can't get across the battery terminals.