A lot of people recommend Betis, after which I took them for my first save. However, I was quite dissapointed in the squad, and I stopped with this save. I know people will say that they've signed Carvalho, Canales and Lo Celso, but that's basically it (and Lo Celso is on loan).
The squad lacks depth, only having 7 or 8 substitutes (of which most are defensive players). Also, it's quite an old squad, there aren't any big talents in the squad, and there's basically no money to invest in the team.
Again, I was quite disappointed!
Udinese is an interesting team to manage, I had a nice game with them in FM2011. However, I'm still not sure which team to manage this edition.