Ronaldo left United last summer in a world record £80 million deal.
He told the News of the World: "In Spain, the players are more technical. They like to play football more than they do in England.
"But in England the players are stronger. They are more physical. The game is more direct. Here, the small teams like to play but in my opinion the Premier League and La Liga are the two best leagues in the world.
"I have less bruises now! But getting kicked is always a problem for the skilful players. I was injured a lot when I played in England. In Spain it is quite similar. I haven't played the whole season here, but I can see a few different things.
"But I think the English League, sometimes, is more exciting. People love football more in England. The fans love the game more."