CJ was a wonderful host. He was very flexible with check in (as we arrived quite late) and also with check out. He also responded very quickly to every message I sent!
The place is definitely as shown in the pictures (and better). The only slightly annoying thing is that the toilet is outside of the little flat/room and you do need to share it with others (if the other room on the floor is occupied). This did not prove to be a problem in any way at all, as there was no moment where we needed to use it and it was occupied. So don't let that put you off! The room has its own private shower.
The flat has loads of amenities, with loads of available towels, toothpaste, body wash etc, along with a small and perfectly functioning kitchenette. The bed was comfortable and the room was warm!
The area is a little sleepy (but with lots of shops around), but a really lovely walk to central Rotterdam. The best of both worlds really!
I would highly recommend staying here!