We had a nice stay at Esser's place, and overall would recommend it.
Pros: The location: 7 blocks from metro, 5 minute walk to the street food place (so amazing!) 10 minute walk to Nyhavn. Quiet residential street along canal, very charming. Simple and clean. Cute balcony to sit and enjoy street/canal view if it's nice out.
Cons: Not much, really but the main bedroom has a full bed, not a queen, so it's a bit tight if you're sleeping two and used to a Queen. One of us ended up sleeping on the living room futon with our 2 yr old so we had a bit more space.
Also, the t-molding between rooms is raised a few inches, so if you're traveling with a little one or just clumsy like me, there may be a few toddler wipe outs or stubbed toes before you learn your lesson.
It's pretty clear in the descripton I think, but in case you miss it, you should also be aware that it is a walk up (4 floors),but if you indulge like we did at the street food place, it's kind of a good thing ;)