I stayed at Marina's for a few days.
The best: The flat's location is quite nice, in a green and safe area, very quiet. I rented a bike and it was very enjoyable. I was preparing for a university lecture and I could work nicely there, the internet was very fast and reliable, and the room was well-equipped for that. It was warm in cold nights and I didn't miss a thing.
Could be better: My stay and first contact with Marina was a bit strange at the beginning, and I felt a bit nervous during the stay due to this. I opted for spending most of my time outside. It went better in the end; she has good intentions, but I still felt a bit awkward at times. As other reviews say, there are no supermarkets at near walking distance so stack up when you're around. Bear in mind there's a microwave but no stove nor sink in the room. The room could have been a bit cleaner as well.
I think your enjoyment of this place will 100% depend on your own standards. It definitely doesn't offer a hotel-like experience nor its comfort, but it also has a unique touch. Sleep on it before you book :)