We had a place in San Miguel de Allende, in Los Balcones, with incredible views of the mountains and the Obraje. We chose it and loved it for the climate: cool (even cold) nights (on January mornings you might find frozen pools of water); hardly any humidity, even during the rainy few weeks. Incredible countryside with plenty of Otomi holy sites, excellent hiking and biking and sightseeing. Close enough to larger urban areas such as Queretaro and Guanajuato, and good inexpensive shopping in Dolores Hidalgo.
What we did not like was the huge expat community, too huge, which does not help to integrate. But what really ruined the city to us was the insane development, with thousands of houses in dozens of sprawling subdivisions, which stole precious natural land but remain uninhabited. Also the town itself and labour are very expensive compared to elsewhere in Mexico. Good place to visit, but not sure it is an attractive place to live any more...