I visited this WHS in August 2014. After some reading and research I decided to concentrate my visit mostly on the Yuso Monastery which is the bigger one of the two. It costs 6 euros to visit and we were accompanied by a Spanish guide throughout the visit. A leaflet in English containing the gist of what she says in Spanish is handed out but it isn't really all that necessary. The Yuso monastery houses the first verses written in the Castillian language so it is an important national cultural site apart from being a WHS. The church cloister and gilded furniture are nothing out of the ordinary compared to other WHS I've seen. The sacristy though is beautiful. The Books of Gregorian Chant weighing up to 80kg were the highlight of my visit. Two treasures worth seeing are the boxes/chests decorated with the original 12th century ivory plates of San Millan intricately carved and in very good condition. The exterior is worth a quick photo mostly for the serene environment surrounding the Yuso monastery. The Suso Monastery is very small compared to the Yuso Monastery and there is a shuttle bus that takes you there and back every 15 minutes departing from in front of the Yuso Monastery. Entrance tickets (inclusive of shuttle bus service) are sold at the Yuso Monastery. I enjoyed my visit as another stopping point on my return road trip from Portugal but it's definitely not one of Spain's best WHS in my opinion.