I'm a mechanic/body man & always working. I use a puresmoker v3... it's all stainless steel & very durable. it has a screw lock on the switch so no accidental firings. about the only problems I've had are with carty's, they can easily be snapped off & give you a nice wet pocket full of juice... since switching to a regular 510 atty with drip tip almost no problems... the worse case might be breaking an atty but that would take serious abuse, I haven't completely broken one yet but have kinda bent a few... they keep on going...
the v3 is not small, but it is a serious hunk of stainless steel & very durable, I've dropped & abused it many times with no problems... well one problem really, & that is, if you happen to drop it straight down & it hammers on the switch when it's in the unlocked position, this can compress your batteries a bit making them just short enough to not make contact, but even that isn't such a big issue cause yo can just loosen the contact screw inside at the switch a bit to make up for the difference... overall it's almost bullet proof ...