I loved my 1 room unit at 18 Hanover! Very quiet, close to all the Royal Mile attractions and castle. There was a room being painted in the unit next to mine, so there's strong paint thinner fumes in the hallway, but they dissipate soon as door is closed, I didn't find them troublesome.
The unit was very clean and looked newly renovated, with clothes washer/dryer, dish washer, mini fridge, espresso machine, rain shower head and hand held shower head. There's no outlet in the bathroom except for a razor (two prongs) so I brought my own extension cord to use the blow dryer and hair curler in the mirror.