I just purchased a Trek 4500 last night....I've only had a chance to take it for a spin around the house and up the street...but so far I love it! I am by no means an expert with bikes, but I am really impressed with the package that comes with the 4500 for the money.
Personally if I were you, I'd go with the Kona Fire Mountain. For this price range, I did a lot of searching. It's the only butted frame with 7005 aluminum. It has a Marzocchi fork, even if it's not a high end fork, it's still a Marzocchi, and the overall package is really nice.
With the Trek, you get a decent frame that's going to be heavier, a decent suspension which won't be as nice as the Marz, but you'll get higher level componentry like Deore derailers (I believe, if I remember correctly).
It's all a trade off. I figured I'll break the derailer anyway off some rocks or something, and have to replace it anyway.
It's a nice bike, but my personal preference like I said is the Fire Mountain. Not to mention I own it and love it.