The apartment was wonderful -- spacious and quiet. The arty feel of the place was great. We thoroughly enjoyed the neighborhood, which was friendly and vibrant, but outside of the touristy places (though those were quick subway rides away).
Mei met us at the apartment and offered us lots of useful information. Do go to the Catalan restaurant she recommends! Sergio even checked in on us to see if we needed any help with anything. Very thoughtful!
One caution about the apartment: It is at the top of five flights of stairs, which may be challenging for older folks. We didn't mind them at all though.