Les Stroud tried one in an episode of Survivorman and had a hard time getting it work...though it did work.

This is my opinion of course but I'd be worried about their longevity...gaskets can fail, pistons can leak, shafts can bend. And as far as I know field repair would range from difficult to impossible.

Less mechanical than a Bic or a Zippo but those are easily and inexpensively replaced...firesteel on the other hand doesn't really break (unless you're incredibly unlucky or careless).