My opinion is probably not shared by many but I do believe that stars are much more important than match ratings. Many of us have done the experiment (and in my case I did it several times): take your worst player and put it in your team out of position, the chances are he's going to be man of the match ! But on the long run, your team performances will be much much better with a 7-star player, even if he's getting average ratings. I cannot prove that but I've got many clues. For instance, I have never been kicked out of a cup by a weaker side in 28 seasons when I lost several times to higher rated ones when their manager was not present. I always rely on stars first and I only consider match ratings when I'm comparing two players with the same amount of stars. Stars first, tactic second, the rest is purely cosmetic.