I prefer to watch Messi as a footballer in free play because I think it is more gifted to be small and play from deep positions and run around a team of players and assist and still be a great goalscorer.
Ronaldo is a great athlete and goalscorer but he is playing as a striker and a lot of goals come from dead ball positions or powerful strikes. He is better at this than Messi but Messi could play as goalkeeper and still find a way to dribble the pitch and score.
The only problem with Messi is that he hasn't led his country to a World Cup or Copa America. Ronaldo somehow has won with Portugal even though it was very painful to watch and not the beautiful game and he was not even on the pitch in the end. But he does seem to win more somehow through will power and work even with less natural talent.