Looking at the site, I would say that no, you should stay away from people selling kittens only registered with these people as the pedigree is probably a poor one. If the kittens had the background to be registered with TICA or CFA or ACFA, they would be.
From what I understand on their site, they aren't just a registry they also pick out the animal for you. That's a broker, plain and simple, they are getting these animals at a lower cost and charging you a finders fee for the same cats you could have found yourself. Any place that has cupons, financing and the like is out for one thing, $$$, and could care less if you end up with a poor quality, sick animal. It appears to be the equivalent of adopting from Petland. Please don't use them, if you tell me what breed interests you and your state, I will look up the e-mails of all the local breeders I can find and you can deal with the breeder directly. Any breeder selling to this place doesn't even care who their babies go to.