Goal-wise his season at Barca is the only season which puts him in GOAT discussion. In the last 20 years or so, I think only Messi in 2012 had a better year.
His longevity is a problem though, as is his relative lack of club trophies (1 league title, 0 UCL in more than a decade playing for the top teams in his country). I also don't look fondly on his Real Madrid years, when Real had won 3 on 5 years, added him and weren't able to go close to winning UCL. They even got eliminated from Fernando Morientes whom he had just replaced. And in Italy, he was consistently outscored.
I think that when he was in song, he was as good as anyone has ever been, but he was nowhere as consistent as the other Ronaldo or Messi. So career wise, I think that he is a couple of levels below them. On absolute peak (season-wise), he is below Messi IMO, and probably around Cristiano's level. If you look at their best ever games, then, he is better than anyone. Essentially, a more powerful and faster version of Messi (without the GOAT passing).