different positions, emphasis on club or international, etc.

Since the Bosman Ruling talent is more concentrated in the top European leagues than ever before. The level of competition that Ronaldo and Messi have faced was stronger than that of what Maradona and Pele faced. I think Messi is the greatest ever but there are some Ronaldo stats that give me pause:

5x UCL champion and the all time leading scorer and assists in that competition

Most international goals of all time

Scored more goals than Messi during the 9 seasons that they were in La Liga together

Has won the League's Golden Shoe on every club he's played for

Hasn't won the World Cup but Portugal's best international success has come in the CR7 era including their only 2 trophies