Ah, the joy of being able to post here, as convinced of my rightness as anyone else. I'm not interested in defending my view, as it won't be changed, but challenges are welcome.
Messi is leagues ahead of Ronaldo in the general playing of football. Messi is leagues ahead of Ronaldo in creative midfield properties, such as incisive passing; the vision to pull off such a penetrating pass; the ability to execute such a pass in numerous different styles; the ability to get out of all kinds of trouble with deft close control and unsurpassed technique; the ability to get out of all kinds of trouble by dribbling past 1, 2, 3, 4 or 5 opponents, and then supplying either the type of pass already touched on above which results in an assist, or the killer finish himself.
Ronaldo barely enters this particular discussion. He does though in terms of striker ability, where he's one of the best that's ever been. Trouble is though, Messi matches him. He's just as good at this aspect of football as dropping deeper and supplying, which isn't the natural Ronaldo habitat. Messi is the complete footballer, but I'm not about to say he's the best that will ever be, as that's short-sighted. Genius does reoccur, and football will still be played in the year 235667. Nothing is beyond him, while there's plenty beyond Ronaldo, or any other player presently kicking a football for money. He can do it all, in often unimaginable ways. He routinely produces beauty. He's an artist in the way few footballers can dream of. But it's not science, and it all depends on what type of football gets you off.