Some of their buildings are beautiful, but I agree many things are substandard compared to the states, which is a big consideration. However there is also a lot more freedom in Mexico, and expenses are much less.
My friend must be including the Rosarito and Ensenada area for the thousands of espats, but that still seems like a lot to be actually living there. Another friend visited there a few years ago and said she didn't like it because all the houses looked like shacks.
Tijuana is like that too, but I didn't seem to notice that much, as the people are quite friendly.
I'm thinking that living that close to the ocean is not for me. Just visiting is a possibility, but would have the risk of getting into a relationship and then ending up living there anyway. I think being more in the mountains and away from such heavily touristy areas would be more to my liking.