Brazil and France for me. only diffence is that regens in Brazil can only be signed when they are 18+, which is very annoying as everyone knows. In France you can sign them without having to negotiate with the club. So maybe the regens are slightly better in Brazil, but I always look first in France |)
For me its Brazil and Portugal because of the shear quantity coming out of those two countries. But I always seem to come across one or two top, top class regens from the Scandinavian countries and for some reason they are probably my favorite to sign.