Dina-Perla was one of the highlights of my trip to Amsterdam. She's so kind and accommodating (even when train problems pushed my arrival hours late!) The cat and dog are bonus hosts too.
The room is a good size, with a twin bed, shelving unit, low table and chair. There were several guests at the same time, but I never had to wait for the toilet or shower. (The hot water is really hot!)
The Museumplein location is great, and there are multiple buses and trams nearby.