I live in San Miguel de Allende and have for about 10 months. I've found it very family-friendly, with a lot to do: horseback riding, fantastic restaurants, bars and dancing, hot springs, art shows, yoga meet-ups, etc. As well, the hospitals in nearby (1 hr away) Queretero are fantastic -- if you go private. There are a LOT of expats here, though most of the younger people are from Mexico City. The weather is the closest I've ever come to being perfect all year: low humidity, and highs of 25-30C. The only thing I miss is being near the ocean -- but I can catch a cheap short-haul flight and be in Cancun or Puerto Vallarta very quickly -- and then leave the humidity when I tire of it.
This is a very charming old town with really beautiful infrastracture and bakeries. I stayed in one of the traditional villas with a balcony overlooking the entire town. I love hanging around in the coffee shop and even starbucks looks artesanal. The weather can get really cold at night so best make sure that you have a heater in the accomodation you are in. It is actually quite cold that you really cant stay at the balcony to enjoy the view too long. Internet is okay, safety is okay.
