Yeah, I've seen them come up with some decent results. Seems like their fare search engine does some pretty in-depth searches for some creative route/fare combinations.

Their downside appears to be the booking fee, but if it's the only site that will allow ticketing a particular fare combination, it's probably be worth it.

Not talked about a ton on FT, but this thread touches on it: http://www.flyertalk.com/forum/onlin...ine-sites.html