If you are really looking to stick to the $400-500 range, you should probably be looking to buy a used bike. Keep an eye out on Craigslist, pinkbike.com, and check to see when your local bike shops do bike swaps (usually spring time). As far as any one brand, that is so hard to do in the MTB world. There are many great companies and philosophies when it comes to building bikes. I have been trying to demo bikes all summer to see which direction I want to go. Jamis, Rocky Mountain, diamondback, Santa Cruz..... That's just the tip of the ice berg.