In the good old days you would drop by your local LBS and try out a bunch of different bikes and buy the one you liked most. Bikes vary in terms of fit, comfort, performance, feel, weight, build quality, durability and visual appeal. I remember in the past I could never get a Giant frame to fit right. They assumed their compact geometry allowed them to get away with making only four or five frame sizes but I always felt I was somewhere in between. The Treks always felt good right out of the box and could be dialed in perfectly by the LBS. Fit is always critical. Buy the bike that fits and feels right.