I think it is probably one of the better cactus nurseries in the Phoenix area. Usually when you talk about cactus and succulent nurseries in Arizona you hear about the multitude of great nurseries in Tucson first, but Phoenix does have some good ones too.
Another good seed source is Koehres in Germany, and I have gotten some good seeds from Rare Palm Seeds.
Yeah, after some interesting experiences on eBay I have learned that while you can find great things on eBay (and probably amazon) you have to be really careful about the sellers because there is a lot of rubbish out there, so now if I buy seeds it is usually from places that I can easily determine to have a good reputation.