I've used Air Guadeloupe several times. It's a pity you can't buy tickets on their website (at least you couldn't 6 months ago). They're a little amateurish, but with small planes (some are STOL; Short Takeoff/Landing, such as to St. Barth's) they're about average for a "commuter" type airline. Don't be surprised by a short delay, but don't also be surprised if they accomodate you on an earlier flight, if they have a seat. We've never had difficulty with the staff-- they try pretty hard. Finding them there, now that's another matter.

In all, I've got nothing bad to say about them, after probably 10 flights. Your boarding pass also regularly has a good offer for rental cars, which I've used twice, getting about 100FF off per day in the off season--- about the best discount available in the French caribbean.

Have a good trip!