First the positives:
Location - superb and close to decent restaurants.
The hotel bar - expensive! But superb cocktails, quiet, exclusive and felt like a high-end members' club.
The concierge - friendly, helpful and exactly what you'd expect.
Quiet location, despite being a 10 minute walk to the Spanish Steps.
But....
The rooms are spacious, but sparse. They feel like a 3* room.
The plumbing is old, so the shower never got very hot and took FOREVER to get warm.
Bathroom amenities were basic and no extra towels.
One, slow elevator.
So overall, better than some, but a hotel which could make a little more effort. But a good stay nonetheless.