Where should I stay in Mexico City?

I’m traveling to Mexico City in July and have been scowering the internet in search of the perfect place. I can’t tell if I am looking in all of the best sites or not. I don’t want to stay in a chain. And ideally I’m looking for something with the feel/attitude of a hostel but the style of a boutique hotel or B&B. Any ideas of specific places or good search sites are appreciated. I’ve checked trip advisor, fodors, and several other sites. I also speak SPanish so local Mexican sites are helpful too. Thanks!