The location is fantastic, there's tons of restaurants all around and a Lidl, Tesco express and a couple of Sainsbury's locals nearby. Arthur's Seat is about a 20min walk away and being above a pub made it very easy to find. Noise level was pretty good too, we stayed for 7 nights and only one of those nights I'd say we had a bit of noticeable noise from downstairs.
The shower is great and having a washing machine is a bonus. The heating was pretty easy to work, we just put it on a timer to come on in the morning and evening since we were out all day.
Grant was fantastic, really quick at responding to messages, we had a problem with not getting any sound out of the TV on the first night, so he replaced it for us asap.
The flat desperately needs updating, a lot of the cooking equipment has seen better days (though Grant did get us a new frying pan since the one in the cupboard was tiny), and I found the bed a little uncomfortable. Otherwise the flat was comfortable enough, just set your expectations fairly low, like it's been said, it's not a hotel, it just needs a bit of love