It's good as a backup lighter, always on my keys, and having the rubber seal i didn't have any fuel evaporating... still worked fine after a few months of keychain carry, but to use it all the time is a bit awkward, unscrew it and screw it back every time, the whole action is not very fast, and the thing is quite small, not the easiest to open it if it's too tight, and its smooth and a bit slippery.
Construction wise, the thing is a small beast. Thick steel walls, rubber seal, overall looks and feels very tough, so it ain't gonna be easy to break it.
I used it a couple of times, when i forgot to take my lighter, and worked as a charm every time. I'm not sure how long you can use it on one fuel charge, but i'm thinking about 40 50 times at the best.
All that said, i do like the small peanut lighter, and never take it off my keys. You never know when it's needed.