Another issue besides fit is whether or not you want to spend your money on the latest trend that the marketing departments are pushing this year. I hope this doesn't degrade into a disc vs. rim brake argument but I don't think road discs are an improvement for the type of riding I do in the region I live in. I see the time coming when every road bike in the lbs will have discs. I also have a strong opinion about chainstay length that runs counter to what is being offered by the big companies. The front end geometry on typical mountain bikes is wrong for the local trails I ride. All of that is easy to overcome with my own designs.
Material choice figures in too. The carbon bikes I've ridden were just plain harsh. I enjoy the ride that I get from steel. Most people think that all steel bikes are heavy but my latest build came in at under 15 pounds for a 56cm frame. As an added bonus, the geo is right for me. That bike has no equilivalent in any line up out there.