I’ve seen several projects use FIT and thankfully I didn’t hang around on them too long. I’ve not been a huge fan of FIT (though I will admit it has its purposes). Thanks to James Shore for writing a blog entry about when not to use FIT (and hey, it’s really not that often you should be!). He’s also very humble enough to admit his mistake around promoting it with his articles on “executable specifications”.
If you’re a FIT fan, have a good read of this.