I've never stayed there but Hotel Nadia has a very good reputation. It's No. 18 on the Tripadvisor list of hotels, the highest ranking of any budget hotel in Amsterdam.
If it wasn't for the amazing bargains to be found via Priceline, Hotel Nadia would be at the top of my list of hotels to stay on my next Amsterdam trip.
It's like a mirror image of the di-ann (other end of the block). Both nice hotels for the money, with friendly staff and great balcony views if yr lucky.
Di-ann just shades it imo, but i'd stay in either again.