The Cosy Corner is a great place to stay in Utrecht! I stayed here for a couple of weeks while working at the University and found it perfect for me.
The owners are helpful and interesting to talk to, and speak good English as well as Dutch. The room is spacious and has everything you need. Its great to be able to cook in the little kitchen too.
The local area is also great - Kanalstrasse, just toward town from the Cosy Corner, is a vibrant shopping district with heaps of small grocery stores. There are also a range of supermarkets in walking distance, a bank machine, a couple of local pubs, and a good liquor store across the road.
I can't recommend this place more - stay here!