I would go to a bike shop such as Performance and invest the money…even the $600 there. You will get properly fitted for the bike and most likely better components for the money you spend. I bought my Fuji mtb there and was so happy with the service and money investment that I go back and even get help to tune my bike etc. They are very helpful in answering any questions and even let you ride the bike in the parking lot to see if you like it.
Shop around and you may get more bang for the buck with a higher quality bike.