Cristiano Ronaldo is absolutely a clinical finisher. He's tied for the league lead for goals in the Premiership with 13 goals. I'd say that's a pretty golden foot.
If you were to compare Ronaldo and Ronaldinho together, you would see that Cristiano is the more effective player.
Ronaldinho himself is a pretty incredible player but his play takes him from the midfield on up. IE, he does not defend, and when he does, he doesn't do it well. If you were to speak to frank rijkaard, he would tell you that Deco is the motor which pulls Barcelona forward, and not Ronaldinho. Ronaldinho is that offensive genius that gives his team an attacking edge, and that's all. Very far from the complete player.
Ronaldo has 13 goals, and 6 assists thus far. He's taken a different roll with United this year making wayyyyyyyyyyy fewer crosses. I think about 68 and about as many shots which is more than he took last year. He's basically the driving force for Man U, and I don't see another player on that team with the creative genius he has. A player which pushes the ball forward as much as he does. His position on the field is sometimes a gray area too. He's regarded as a winger, but he seems to play the wing, a second forward, and a #10 all at the same time.
Cristiano is only 21 years old. Was Ronaldinho as good as Cristiano at age 21? Probably not.
And I'm pretty biased myself, but I think Cristiano will be the best player in the world in the near future.