These investments are made only when a rider is very serious about racing. You may be like this someday, but for now just concentrate on the entry-level machines. Definitely plan on taking prospective bikes out for a test ride. Ride them for a few miles and see how they feel. Some handle better than others.
Some gears are easier to shift than others.
This is the most important part of buying a bike. You must be comfortable with how it rides, especially if you're going to spend any amount of time in the saddle. Most shops offer one free tune-up after the purchase of a new bike. Make sure your bike gets that plan. In addition, many shops offer mechanics classes for a low cost, and these are worthwhile.