I have nothing but good things to say about Jack's place. Jack is a phenomenal host, very kind and considerate, and his apartment is EXTREMELY clean (coming from a clean freak!), and modern. Also, the location is the BEST - next door is Edinburgh Castle, and Old Town and New Town were both right at our fingertips. We loved being able to walk everywhere.
Note that this is a studio. We were a group of 4 women and found the place cozy, though a group of 4 men might think otherwise. However, given the location and the cleanliness of the place, next time I'm in Edinburgh, this is where I will be staying!