I flew them last year, on a 'really incredibly cheap because it's frigging cold' winter fare. Left BWI, went to... LHR? One of those London airports, whichever one they fly to.
It was a perfectly fine little airline. In the winter it was uncrowded. I had an empty seat next to me on three segments, and a full row on the fourth. You always connect through KFL? -- whatever the abbreviation for the Iceland airport is. I can't even remember the name at the moment, long day at work.
I stayed a night in Reykjivak. It was neat to say I'd been there, but there really wasn't much I could see in 24 hours in the middle of winter. I did have a nice conversation with the hostel owner's daughter. And I saw a bit of the city. It was dark and cold, though. And the museums were in Icelandic.
The meals, for picky eaters, were a little 'weird'. I think it was fish. Or maybe I just remember it being fish because I don't eat chicken or beef. It struck me as a little funny, but then, so do Air France meals. Like I said, I'm picky. Perfectly edible, though.
Oh. And the Hard Rock t-shirts in Iceland, bought at the airport, have about a 100% markup. Maybe not quite that much, but significant. I had dinner at the Hard Rock (which is at a mall) and found them lots, lots cheaper. I think it was like $22 at the mall, $38 at the airport, or some such.