Been using this for about a month now for winter camping. Took a bit to figure out how to hold it best- I have some big hands, and this thing is TINY! But it works great- throws some nice sparks, hasn't failed me so far.
I decided to try this to cut down even more on the space my gear takes up(weight wasn't really the issue, but the tiny tin takes up so much less space). Sure, it's a bit harder for me to hold, but it works! Not to mention, the tiny tin holds the striker, a piece of flint, three condensed balls of tinder I made(fluff 'em out to make a nice bird nest), two small lengths of string, and a decent amount of charcloth. That all fits perfectly in the tiny tin that comes with this.
Basically, the issues I have with this come down to my having big 'ol hands- but it works very nicely, takes up virtually no space, and makes fire!(as it should, being a firestarter)