A nice place, but a bit far away from the city center (too far for walking). However, tram lines (and metro) are nearby, so it's not a huge problem. Also, there is a very nice park (Erasmus park; great for a picnic), and a few places to eat nearby.
The hosts were very welcoming and provided us with all the info we needed for our stay. The little dog that lives in the house is very adorable and friendly.
Note: the stairs leading to the apartment are very steep and narrow, so it might be difficult to reach with large luggage or by someone who is not very fit.