Of the recent guns some of the names to look for are Ugartechea, AyA, Grulla, Arrieta, Garbi, Arrizabalaga, and Kemen. These are all quality guns and I don't think that you can go far wrong with any of them. As with any gun check what kind of dealer and importer that is behind the product. You will be dependent on them for parts and things like choke tubes.
Spanish steel and spanish barrels used to be the benchmark of quality in the field. Then American companies went to Spain, Italy, and Belgium in the fifties and sixties wanting to contract for cheap double guns. Unfortunately some companies took these contracts and the image of the products that these countries made suffered. There are plenty of old Belgium clunkers out there. Likewise Italian guns used to have a bad rap until Beretta and Perazzi among others pulled the reputation of Italian shotguns out of the dumper. It has been a longer period of recovery for the spanish guns. This is not to say that there are not some real junkers that have come out of Spain from time to time and have been dumped on the American market.
Be careful and do your research before you buy.
Chuck Graber
P.S. Be a little careful of Ugartechea and AyA doubles that are more than about 20 years old. Some of these older guns had some problems with soft metal and in the case of the AyA matadors, cantankerous single triggers.