In term of attitude, I would go for Brazil's Ronaldo but in term of flexibility and effectiveness for modern football, I would go for Cristiano. But it's hard to compare a winger with a striker. Better compare Brazil's Ronaldo with Messi.
When Cristiano was playing for Man.utd he was better as the Ronaldo of Brazil (at that point). Now i don't know since i am not following the brazilian soccer league. Atleast i know that Ronaldo of Brazil (before all the injuries) have been a better player then the current Ronaldo of Portugal.
I think Ronaldo from Brazil is more best.. he not just success in club also for his country not like CR7..
I would go CR coz he is a play maker with an amazing ability to score goals. but Ronaldo senior was an exert scorer. Stop the flow from the deep he becomes a venom less snake. Ronaldo Sr. has to depend on midfielders to give him the pass. CR can do everything himself.