We've been on two cruises, Caribbean/Mexico both times. We've ported in Costa Maya, Cozumel, and Calica. We've enjoyed these ports (Cozumel more than the others).
Now we're considering a Mexican Riveria cruise from LA, stopping in the usual, Puerto Vallarta, Mazatlan, Cabo San Lucas.
How does the Mexican Riviera compare to the Caribbean side of Mexico? Weather, atmosphere, activities, etc. Having never been there I'm just not sure if we should go that direction or stay on the east side of the country.
Puerto Vallarta is clearly one of the most beautiful cities in Mexico. (Oaxaca is its only rival in my opinion.) It is so beautiful it is almost an injustice to see it from a cruise ship. The good news is that you will get a taste and want to return for a land cruise. We go there every year for at least ten days and have stayed as long as a month. There is so much to see and do.
One of the nicer things about P.V. is that it has retained some true Mexican culture while some of the eastern ports are much too touristy. That's not to say that P.V. is noy "touristy," but I think it is a very nice blend of U.S. and Mexican culture. Shopping for folk art in P.V. is great!
I'm not fond of Mazatlan. If you go there, either just find a nice hotel/beach and hang out or take a tour of the nearby colonial villages which are far more interesting than Mazatlan.
Cabo is quite touristy but has a lot of natural beauty. Most ships only stay there a few hours which limits just what you can do. Deep Sea fishing is a great option there. Having once caught a 104 inch sailfish, I must say that is a real thrill.