Karin's apartment is a great option for anyone looking to visit Amsterdam. Our flight arrived mid day and Karin worked with us to have her son meet and invite us into the apartment. Karin's son went over the house rules and local recommendations with us as well which was nice.
The apartment was as advertised cute, clean and in a fantastic location. We found the central location to be particularly helpful as we could easily walk everywhere. The area felt safe as well.
The only downfall to our stay was a fair amount of construction noise up above that sometimes woke us in the morning. Beyond that, Karin and her husband were as friendly and hospitable as possible. I would strongly suggest considering staying here for your next trip to Amsterdam!