First off... my choice is Messi. That said, they are all exceptionally talented players, and none of this is meant to disparage any of them.
There are many ways to tackle the question of who is the GOAT. Everyone will choose different criteria and weight factors differently. I left the question deliberately open-ended to avoid skewing the results. Do we consider the eras in which they played, and if so, how? How do we weigh team achievement and how do we tackle the level of teammates they got to play with and the level of opposition they played against? What about the quality of equipment? Medical advances? Venues?... and so on.
I chose to consider this question through the lens of who is the absolute best player, as opposed to the best relative to their time (although my choice would still not waiver, but the gap would get smaller). With that in mind, I believe that right away we can eliminate Pele and Maradona from the mix. The sport has evolved, and the general level of skill has greatly improved. If you put Messi or Ronaldo back in the time of the other two, they would absolutely dominate. Pele's highlights in particular really starts to show its age. The game was so much slower and the defenders were of a significantly reduced level of quality. That's the simple evolution of the sport, especially across such a large time frame.
So that leaves us with Messi versus Ronaldo.
Goals - draw: Both are exquisite goal scorers; the very best. Ronaldo has a few more career goals (while playing in more games), but Messi can create more with less.
Dribbling - Messi wins: Messi is the single most effective dribbler the game has ever seen. There may be guys with fancier moves, but no one who is more effective in game. He can dance around multiple high level defenders as if they were pylons.
Aerial abilities - Ronaldo wins: Messi is simply too small, while Ronaldo is absolutely world class in the air. Ronaldo's jumping ability is outstanding.
Passing/Playmaking -
Messi Wins: Messi is a magician when it comes to playmaking and Ronaldo doesn't even come close to him. Ronaldo also has the tendency to be a more selfish player on the field.
Team achievement - Messi wins (slightly): Trophy-wise Ronaldo has done a bit better internationally while Messi has the edge in terms of club level hardware. That said, there are many external factors at play and when we couple that with how close they are in this category, one can easily consider it a wash.
Individual Awards - Messi wins - The Ballon D'or is the biggest one, and Messi's 7 is simply numerically superior to Ronaldo's 5
Expert opinion (professional players, coaches, analysts/commentators) - Messi Wins - when this very same question is presented to these people, a significantly greater number of them tend to go with Messi.
X-factor (the beautiful game) - Messi wins - Some things simply can't be captured within the confines of statistics or in trophies raised or championships won. The true beauty of the game of football has to be seen and experienced; numbers on a page are simply blind to them. Ronaldo has given the world many spectacular moments that inspire awe, acclaim and respect in equal measure. He embodies human potential at seemingly its very peak, but Messi throughout his career has risen to the level of superhuman. Achieving levels of play that one might only expect from a scripted movie character or within a Playstation game. He marvels and defies what is deemed possible with his every step. Don't believe me? Look up both his and Ronaldo's 50 best goals across their careers. Both are spectacular, but they are not on the same level. There is world class and then there is Messi class; a population of 1.
This is a bit older, but I'm sharing it for its poetic value:
