We stayed here for almost a month and really enjoyed it! The location within Amsterdam is about as good as you could get. It's a few blocks from the Rokin subway stop, but the apartment is close to everything that we ended up walking almost everywhere we went. The place is spacious, cozy, nicely-designed, and has tons of natural light. You can even see the canal and historic buildings from the lovely little balcony.
Machiel is a great host and lives in the same building, so he's nearby if you need anything. We had a very minor problem and a repairman need to come to the house, and Machiel brought by a bottle of wine for the inconvenience — so nice! Because we were staying for so long, he also had someone come clean the apartment once per week which was an unexpected treat. We'd definitely stay here again if we came back to Amsterdam.