We just returned from a week stay at the New Holland house and it was great. The house is perfectly located about 2 blocks from the Anne Frank House and makes the entire city accessible by walking or public transportation. There are great food and shopping options close to the house too if you don't want to go too far.
There was a little glitch on arrival - nothing big, just a mix up of who had the keys due to some maintenance issue they were addressing just before we arrived (broken microwave plate - nothing big!). After a cup of coffee at the hotel next door, however, we were in and set.
The house was clean and had everything you could need. The kitchen is fully stocked with dishes and cooking supplies if you need. There are several markets within a couple of blocks to stock up on supplies in the kitchen as you'd need. There was ample coffee and tea already in the house. The sheets and towels were all clean and comfortable and the house feels lived in and inviting.
One notable thing about the layout of the house. As expected in an almost 300 year old multiple renovated European house, the layout is a bit strange. The larger of the two bathrooms is on the first floor off the kitchen. There is a small, perfectly usable bathroom on the 3rd floor near the bedrooms, but it is SMALL. It does have a toilet, sink and shower though. A careful note about the stairs...they are no joke. They are narrow and twisty. If you have ANY difficulty navigating stairs (bad knees, etc.) you may want to reconsider this location. Even without any trouble going up and down, we definitely found ourselves planning ahead before going up or down to make sure we had everything we might need as to not have to go back again. Getting luggage up and down is certainly a challenge.
All in all, though, this is one of the coolest places we have ever stayed in Europe and you truly feel like you are living in Amsterdam for your time there. I would highly recommend the house!