I stayed at the Hotel Van Walsum three times this year, June/August/October, for five nights each visit. It is very quiet, particularly with rooms facing the back of the street. The location is terrific - 10 minutes by taxi from the Centraal train station, a 10-minute walk to Erasmus Medical Center, but most importantly a 2-minute walk to one of the main walking streets of Rotterdam, Nieuw Binnenweg, where one can walk for 30 minutes for a couple of miles! There are any number of restaurants, bars, clothing stores. There are two grocery stores within walking distance, if you plan a stay of a few days.
Hotel Van Walsum has refrigerators in each room, wireless, 32 tv channels including English language (and 1 German I think).
Breakfast is typical Dutch style downstairs in the bar-lounge area, with an inviting patio just one step out the sliding glass door. Typical Dutch style includes eggs, breads, cheeses, lots of meats, cereals, plus tea and coffee from a real coffee machine. Newspapers are available, although I just read on my iPad using their wireless.
I have stayed at vastly more expensive hotels in Holland, one in Rotterdam and one in Amsterdam, and really this competes with both of them. There is no pool or fitness center, however I had all the exercise I wanted strolling along the walking street.
Staff is friendly, accomodations clean, lots of amenities, with a wonderful location that has little street noise.