I bought a Diamondback last January and have put it through the paces this year. I'm 215 Lbs and push this bike. Although I wasn't very knowledgable about bikes when I bought it, I have since found out that I got a great deal. For $400 (on sale, list was $600), I got Hayes discs, Deore front and rear, and great Alex Rims/Deore Hubs that have withstood much abuse (trued once). It's a bit heavy (@29 Lbs) but who cares, I lost 20 Lbs since I started riding it. Almost all my riding is intermediate/difficult singletrack.

Diamondback's current lineup still has the higher level components than other bikes in a similar price range.