Tbh, I havent really played as a lot of teams. Mainly Arsenal and had a couple of small games as AC Milan, Valencia and Aston Villa.
Villa is actually quite fun. They have a good squad a good transfer budget to improve it if needed. You could give them a try. Valencia too can be quite a challenge. The problem is they have literally no transfer budget left when you start the game. And while its pretty easy with the first team, the challenge really lies in when you get a few injuries (as I did, had Villa, Silva both out for 2 months and Joaquin out for 7months!! Lol). Their backup is not the best
imo so it takes some doing to keep going with them in that case. I only managed to complete the first season with them and came 2nd, a little behind Barca. Didnt really want to pursue after that tbh. But it was a bit of a challenge to play. I kept getting injuries to Silva and Villa here and there and that made it hard. Forget AC Milan. They are pretty easy to play especially one or two seasons. I suppose the real challenge with them would come after season 2/3 when you have to rebuild most of the squad because of their age.