I stayed at B&B Margot earlier this month with my partner and my father (we occupied both of the only 2 rooms!) - we had a fantastic stay. The rooms are bright & airy and the location was fantastic. We walked practically everywhere - Central Station (10 minutes) the Anne Frank Museum (10 minutes) and to the Museum District (30 minutes - but a very pleasant walk) from there.
The beds are comfy, the breakfast is top notch as Margot uses all of the best local produce, and we felt very relaxed and at home there. It was a very personal experience, far better than a generic hotel stay!
Would definitely recommend this place, it played a big part in us having a very enjoyable 2 day break in Amsterdam!