The apartment is smaller than it looks in the pictures, but okay for 4 people. Be aware that the front room faces one of Edinburgh's bigger roads and is therefore very noisy. The kitchen is a bit ill-equipped - in total I'd say it's a great place to stay if you want a place to sleep, not 100% if you want a place where you want to spend a lot of time cooking and hanging out.
Apart from that: nice location, it's a quick walk to anywhere, and Alberto was really attentive.