This doesn't really answer your question...

While we weren't guided while we were there, my impression is that you'd be equally served to sleep in Mulas like (nearly) everyone else. Indeed, folks were sleeping and showering at the Refugio, but frankly, what's the point? I assume there might be a tad less noise and the beds might be a bit softer...but maybe not. Other than the Internet and phones, the place was a touch on the primitive side.

Whatever suits you, man. Refugio is only a 15-20 minute walk from Mulas.

Some of the smaller guide services use the Refugio. For example, three of us went with a pair of guides local to Ecuador. They arranged some services through El Refugio. We actually camped in tents right outside the building and had access to the bathroom facilities there as well as space in the hotel. We could hang around in common areas inside, play ping pong, use the internet comfortably (with a fee of course) and most importanly we were able to use a common cooking area to prepare our meals. That made things more enjoyable than trying to cook outside in bad weather. Note that the place is not heated and is indeed primitive, nothing like a "real" hotel. We had the option of sleeping in a bed there if we wanted to, but it was expensive and we were never inclined to do so. I really liked the arrangement we had. As for showering - its over rated . I was on the mounatin for 2 weeks and never "took advantage" of it. It was just too dang cold there to be appealing. The water may be warm, but where you shower might as well be outside. Not to mention that 7 minute limit and most likely poor water pressure would have just made my greasy mess of hair worse than it already was. If I were a guy it might have been different.

Yea, whatever suits you. We passed it coming down and after two weeks wiith no shower and in the tent, (crappy weather up high), I don't think any of us thought "oh man!!!"