I would say there are excellent bargains out there. Though internet companies allow you to try before you buy, Id say that is a royal pain in the a**.
My preference would be to be able to hear them locally via a rave or someone who is kind enough to let you come over and check them out, or read sufficient amounts of reviews, take the average and just jump in, if they are not really expensive.
Through reviews I have bought the Candela (excellent tube preamp), my Merlin VSM MXs (dopey awesome), and my Nuforce amps (killer x2) Ive done pretty well this way.
Mike