We spent 3 nights at Willem's place.
We really enjoyed our stay there, Willem is a great host, the place was clean, well equipped and maintained.
The location is superb if you don't insist staying in the city center, it's not crowded at all, very quiet, but still quite close to the downtown: about 30-35 minutes away by public transport and maybe a bit less by bike.
I'd definitely recommend renting a bike when staying in Amsterdam. If you cycle to/from Willem's place you'll see many different faces of the city and you'll also use the (free) ferry. It's a unique experience for sure.
Thanks a lot Willem!