CR is better in headers, PKs, and has a better weak foot.

In terms of impact on the field, effectiveness, efficiency, and area of influence they are not even in the same ballpark. Messi is better at dribbling, passing, through balls, creating on his own, assisting, scoring from the 6-yard box, scoring from 18-yard box, scoring from outside the box, at one-on-ones, and better value-added to the team based on advanced metrics.

Based on that, I wouldn't recommend taking Ronaldo over Messi.