We stayed at the Yagan House hostel for two nights in total - one night before and again after trekking the famous W trek in the Torres del Paine.
Remembering that Yagan House is a hostel (not a hotel) we were very pleased with the place overall. The beds were super comfy, the decor was cute, breakfast was great (coffee, eggs, toast and jam), and the staff tried to be as helpful as possible. The reason I'm not awarding full marks is that we paid for them to wash and dry a bag full of laundry for us to take with us onto our next destination. We were booked to depart on an early morning bus, and were concerned that there might not be enough time - but the staff promised everything would be ready in time and told us not to worry. In any case, the next morning as we were leaving they handed us a bag of wet laundry without a word of explanation... we only discovered our clothes were all still soaked wet through when we arrived at our next destination in Argentina - not a good surprise!
Overall this is an attractive, friendly place to stay and a great base before and after visiting the Torres Del Paine. Just don't give them your laundry!!