I have stayed at the Connaught about 5 times and its always perfect. The service is intimate and personal and the location is superb. I always stay in the rooms in the new side of the hotel as the bathrooms are gorgeous and luxe. This hotel has an elegant and luxurious London feel with the modern amenities you want in your hotel room.
The rooms are not huge (but good for London standards) but they are comfortable and have everything you want especially on the newer side. I don't care for the bathrooms in the older part of the hotel so my tip is to book on the new side. Also, the back bar is one of my fav in London and breakfast in the front room is perfectly English and wonderfully executed. I love this hotel.