The way the bike fits should be the deciding factor. Most people are brand loyal, so don't get caught into that trap. All three brands you named are of good quality, and the models are all comparatively priced based on components. Although I favor rim brakes you may find that you like disc brakes. The additional stopping power in the rain is a bonus, however you stated you do not ride in the rain so it makes no difference to you. Rim or disc, get the bike that fits your body best.