Mexico permits essentially no immigration - unless you come with plenty of money. Puerto Vallarta has been a bit of an American colony for many generations.
A friend just returned from a destination wedding in San Miguel de Allende in central Mexico. It's a World Heritage site. He loved it - said it felt like Seville but with lots of Central American Indians. Turns out it is popular for expats and American retirees - 20% of its population is non-Mexican. Due to its altitude, it is always Springtime there.
Lots of lovely antique boutique hotels, inexpensive
10 Reasons Why People Fall in Love With San Miguel de Allende. There's one error in that HuffPo piece: There is no way that famous 1880 neo-gothic church facade was inspired by Gaudi. Seems unlikely.
I enjoy Mexico, but not Cancun and Cozumel and all those drunks and college trash. I think I'll plan San Miguel for next winter, then maybe hop over to Puerto Vallarta for some water and beach.