First visit this winter. We both had the enchiladas suizas, as usual. These are by far the best suizas I've had outside of central Mexico, plus they have been consistently excellent since the restaurant opened (in 2001, ims). The tomatillo suace is outstanding. In numerous visits, we've never found anything as good as the Suizas here -- but are open to suggestions from other C.A. fans.
For dessert, we had tres leches, which was good but a bit oversweet. Our current tres leches fave is at Cafe San Esteban in Santa Fe, where it's more delicate, and presented with more flair. The pink icing is a minus, but the flavor & texture are near-perfect.
Cien Anos is a pretty place in Oro Valley, at the SW corner of Lambert & La Canada. Avoid driving up La Canada from the south, as there is heavy construction from Magee to the Canada bridge. Call ahead at busy times.