Excellent post by JustAnother1K. Just to add in my 2 pesos worth, I thought that many of the gay guys in Mexico City were very friendly and had much less attitude than in many other cities. I barely got to Condensa when I was there, but what I saw was really cool, and I will go back on my next trip to el DF. If you are staying in a hotel in Zona Rosa, there is a nice coffee shop/dessert bar on Amberes that is very gay, and a nice break from the bar scene. It is almost at Reforma. Across Amberes is a medium sized gay bar called Lipstick that was not bad.
Do be careful with taxi's there though. I got scammed by a street taxi pretending to be a radio cab. He took me for about 250 pesos, it was more the principle of the thing than the money lost. My best advice is to maybe ask your hotel if they have any drivers they know and work with and just hire one for the evening. They will drop you somewhere and be waiting for you at a pre-determened time and place of your choosing.