We stayed in the 'Embassy' apartments which are part of Castle House apartments - check in was super easy, was simply buzzed in using the intercom and the keys waiting inside.
While we only stayed for one night, it has everything you would need as a great base in Reykjavik. Clean and comfortable, excellent shower, and just a few blocks from central Reykjavik. The apartment was studio style, with small separate kitchen and bathroom. Definitely recommend.
- Free Wifi