messi has succeeded in one country with much of his playing time being with possible the best club side ever. Ronaldo has done it in the three biggest leagues in the world. Also, you are possibly not old enough to have seen Pele (and very possibly prime Cruyff)
Playing for more clubs doesn't make a you a better player, Eto'O isn't better than Cruyff just because he shined in more clubs than the dutch.
And Ronaldo played in a very poor Serie A btw, when Juventus had no competition for the title, not like he was playing for Fiorentina or Roma.
Messi is better than Ronaldo, at dribbling,passing,free-kicks, and playmaking...the only area where Ronaldo can be better is scoring, and that is still debatable because Messi has better goal per game ratio than Ronaldo.
Most non-United, non-Madrid, and non-portuguese fans, recognize Messi as the better player, cause they have no sentimental attachment to a club where Ronaldo has played.