Mountain Bike purchase advise.

Question
Michael, I have been looking into purchasing a new mountain bike for a while now.  My problem is that there are so many models to choose from, I don't know how to narrow it down myself.  My main concerns are durabilty and cost.  I'd prefer to spend less than 500, at most 600.  My last bike was a Schwinn Aluminum Comp sold at Wal-mart.  It held up ok untill I started riding more aggresively on trails.  Then I started having problems with bent rims, broken derailers, etc.  So I need a tough bike.  I have been recommend the Trek 4500, Gary Fisher Marlin.  Do you think these bikes will serve my purpose?  Do you have any other bikes in mind that are in the same class or one class higher (not over $600).
Thanks
-Nathan

Answer
Hello Nathan,

This price can offer you a good bike and parts.
But only if you maintain these components good they will serve you a long while.
But in these pricecategory you have nice bikes, i can't recommend you a specific bike, but buy a brand like you allready mentioned.
The Trek and Gary F are good bikes, also a Cannondale is, only there you'll have one of the best frames ever. But at the otherhand the component are cheaper, but these you can change for better one's when there are weared out.
How higher the price, mostly the quality is better.
Like SRAM 9.0 or XO or Shimano XT/XTR are extremely good.
See reviews at www.mtbreview.com

Good luck

Michael