I love Messi, it's hard to find such an individual blessed with amazing technique, dribbling ability, superhuman sprinting ability in addition to other underrated faucets of his game like mental strength, poise under pressure, calmness etc. He got elbowed in the face by marcelo and was spitting blood, but he didn't complain or dramatize his injury, or lose his rag. Instead he just carried on the match trying to poke holes into Real's defense until it breached.
Maradona was a superb player in his right, probably my favorite player ever growing up. He did have a shorter career, but my God he was amazing. He was scoring from 40-50 yards at Napoli, he was just outstanding. And yes, he did play in a tougher, more defensively minded league Xxavi - I'm sorry you can't compare Serie A of the late 80's early 90's with La Liga. It'd be like facing Juventus like defenses every fooking week.
But Messi wins on longevity and mental strength. If Leo could win a WC it would end the argument forever. He hasn't, so it goes on.