Are they popular? Well, based on the number of ships in the Mexican Rivera, compared to the number sailing the Caribbean, you wouldn't think them popular, as there is probably 4 or 5 times as many ships in the Caribbean. But they are still attractive...many people love them. For those of us on the West Coast of the US, they are very easy, and reasonably priced.
The general nature is similar to the Caribbean, but a little less focus on water sports.