Piolin is top-ranked in most all markets, but Cheto is definitely a great competitor. I would say it all depends on where your audience is from. If you have a high concentration of audience from Michoacan, from which Cheto hails, it's a no brainer. Piolin probably does better though with second generation Mexican-Americans due to content.
You can't go wrong with Piolin, and he deserves a lot of credit, even though I personally can't stomach the show. My own taste is for Cheto, but again, I hearken back to the fact that it is your audience who makes such a determination, not you.