Don't get hung up on brands. All of those are great brands with excellent warranties, if you need it.
Ride the bikes, and choose the one that suits you best for ride and fit. Ask around your area for recommendations for a knowledgeable shop, which is probably the most important part of the decision. There isn't much difference between frames made by the top level manufacturers, in each price range, but there are huge differences among shops. Choose a great shop, and buy what they carry.