We stayed at Pablo's space for a week in early September; it was wonderful: great location, comfortable space, well ventilated (so not unwelcomely hot at all). There were two of us, and I think we could have fit a third with little sacrifice in comfort. Four might be tight, but I could imagine a quartet of younger people finding this similarly appealing. I really enjoyed the stay; should I return to Madrid, it'd be my top pick again.