This thread helped me with my choice a year or so ago. I would encourage anyone who isn't sure about what spec/CPU etc they want to take a look at the results but also to read the thread as there are some very good posts on it!
I've experimented across a number of leagues across the years but always come back to my Dons saves as being most enjoyable......especially if I can get them outperforming real life!!
Large database and then add in all continents to get all players.
And I mainly play FM, with the odd dose of other games (Madden, F1 mainly) lobbed in.......