For me both are the best where one has more talent than the other, but the other is more complete, Messi takes the talent and Ronaldo the work.

For me the difference that I have noticed between the two of them in recent years is the appearance in important moments, for me Cristiano Ronaldo has been a player who has stood out the most in those moments, almost all the champions that Madrid win there was always an outstanding performance where the Portuguese came back from games scoring 3 goals and most of his goals came in elimination rounds, while Messi has been left a bit of a duty in those instances of high need.

I still think that Messi as a player has more quality, more technique and that is why it is very difficult to keep just 1. Greetings!