Have you tried going on the Neopets 'Guild Board'? It usually moves quite quickly. You will probably have to check out quite a few before you make any decision, but
some of the guilds which recruit there are quite well founded and already have many members.
I see your point just browsing from guilds home. Also there are many good private guilds out there which you can't view until you get an invite.
I can't really recommend any specific guild because what one person views as good, others may have a completely different opinion.
Sorry I can't help any more. Good luck!