Back from Mexico so I figured I'd reply to my own thread in case anyone else has similar questions.

The restaurant at Casa Reyna was absolutely excellent - I highly recommend it! A Mexican friend and others who have been told me they have the best mole, and I wouldn't argue - it was delicious, if a bit heavy. I ate at the restaurant three times, each time getting different things, and each time I was extremely satisfied. I think my favorite meal was the salmon in two pipianes (red and green); it was very flavorful; the fish was cooked perfectly, and it wasn't as heavy as some of the other dishes you generally eat in Mexico.

On the flip side, I also ate at El Mural de los Poblanos, which has the reputation of being one of the best restaurants in the city. I had adobo chicken, which was also delicious - but a couple of hours later, my stomach was, shall we say, not having it. Admittedly, these things can happen in Mexico, but that was a big disappointment.

Otherwise, I took a day trip to Cholula to see the pyramid/church they built on top of it. I really liked the town, the state museum right next to the pyramid site was surprisingly interesting and very well laid out, and I had a lovely lunch. The town had a very relaxed feel to it, and everything was a comfortable walk from the main square.