In terms of footballing both are pretty much at same level really, in terms of skills, balance, pace, technique, first touch, shooting, dribbling, passing, flair, vision, playmaking, freekicks etc (Messi probably plays better one-twos, better finishing/composure and more efficient, while Maradona probably scored better freekicks, more explosive and more flair etc)
The main difference here is, Messi basically has better end-products (much more goals and probably similar assists numbers?*), more consistent, better discipline, and performs better at club level.
Maradona is more influential (much better leadership, always pose big presence on the pitch despite small body size, and can carrying team on his own), big game player, and performs better at international stage.
(*I've read somewhere Maradona has over 300 assists, giving him over 1 goal/assist per game over his career)
Lets enjoy watching both.