When I first went on the Aragonese, I stayed at the Hotel Aragon on the N240 by the turnoff to Santa Cruz de los Seros and San Juan de la P, and found it basic but comfortable. The meal was good and the innkeeper friendly and helpful -- or at least he was 10 years ago!
About 8 years ago when I went through, I stayed at the Hosteleria in Santa Cruz itself-- it was busy and tourist-focussed, but I had a very nice room with balcony overlooking the church, and the staff was friendly and helpful-- the food was good if not outstanding. Prices were fairly reasonable at the time.
The third time I went through (2009 IIRC), there was a fiesta in the village and the staff at the Hosteleria warned me that the speakers were set up right in front of the rooms, and there would be no chance of sleep that night. They called to the Hospederia Monasterio up at the new monastery at San Juan de la Pena (new meaning 18th century-- it's about 1-2 km beyond the historic monastery) and with some energetic bargaining, negotiated the price down for me from stratospheric to outrageous (about 80 euro). My room was very comfortable, although big enough for a small albergue. Unlike most tripadvisor reviewers, I found the food fairly good-- the menu was 12 euro-- and the breakfast decent, although the staff in the morning seemed more than a little sleepy and hungover. I shared the place with a quad club from Barcelona with their machines-- they were very friendly, and gave me a lift to the old monastery in the morning with a very formal and impressive 8-vehicle escort. There's little like a pilgrim arriving thus in front of the morning's first few tour buses.
I recommend San de la Pena enthusiastically. It is like a Maxfield Parrish painting with the pine-covered hills framed by intricate Gothic arches. The cloister carvings by the Master of San Juan are incredible-- they have a vigour and completeness which we could not have understood before Picasso. I count it among the best-kept secrets of Spain and among my top-ten-ever travel experiences.