The location is great and for short stays in Edinburgh where you may not be in the flat too much, it probably works great.
However, I stayed for a month and was in the flat for longer periods of time, so naturally some things were certainly less than ideal. The flat is definitely no meant to be luxurious and is less than others in the area that I saw, but I would say this was one of my least comfortable longer term stays. The internet is horrible and unreliable which was a necessity for me. The lighting is also not good, it's pretty much overhead light or nothing. Neighbors do not seem thrilled this flat is being rented out. Signs all over are targeted at this flat and people will not be shy to accuse you of doing things you didn't actually do. I think 3 times a lady 'reminded' me of the key situation which I was not doing.
Maybe this is just how flats are in the area. Also, I did stay here for awhile. So, depends on why you're coming and how long you're staying. Might be fine for a trip where you are mostly out and about.
Not bad, but also definitely not great.