We enjoyed our short stay at Ruud's studio. It is in a good neighborhood with a local feel, but close to most attractions and conveniently located to markets, grocery, and many cafés.
The space itself is small, but the perfect size for a couple. It is clean and well maintained. We especially loved sitting out on the terrace in the afternoon. I would point out that it is on the fourth floor with no lift, which was hard with our luggage.
Ruud's was a great host. He wasn't there to check us in, but let us know and his neighbor sorted us out. We didn't see much of him, but he was very responsive in the booking/ keeping us updated before our arrival, and was available while we were there for any questions we had.
Overall, I would recommend the studio for anyone looking for a more authentic Amsterdam experience, away from the tourist crowds, but close enough to explore the city.