I'd say in 80% of the games I do online, I end up against Barcelona. Having tried them (as above), I do think they are slightly better than most of the other teams.
I am planning on playing loads with Man Utd, as I do want to play with them and definately enjoy it more, as mentioned above they are quite hard to get the hang of, especially when you are against decent players using Barca/Chelsea/RealMadrid etc.
The problem I have at the minute is my finishing is rubbish a lot of the time, I dominate the other player for say, the entire first half, only to lose 1-0 due to them scoring a lucky counter attacking move.
My other problem using Man Utd (caused by my FIFA09 mentality) is that I usually do a lot better running at people with a fast player, which Berbatov isnt, but his finishing is good, so I need to get more practised of how to play him in properly
One More Solo - you made an interesting point setting your mentality to defensive, so the attacking controls (Defensive/Offensive) etc basically set how high of a line your players play on? Defensive would probably help my being counter attacked against problem quite a lot I would think
It is really quite annoying to play Barca over and over though as Andybtsn says, and this is the point of this thread really, to be able to win using the team you want to play as, not just because they have better players.