We stayed as part of a Soroptimist away-weekend (the hotel used to be exclusively for members of Soroptimists but is now open to all, though shareholders in the club, but not members, get a reduction). The hotel is directly opposite Kensington Gardens, with marvellous opportunities for walking to Kensington Palace, Hyde Park and the Albert Memorial and Hall. A bus just around the corner took us directly to Westminster, and the tube is a few minutes walk away. It's a 10 minute walk to Paddington mainline station.
The rooms are small but comfortable. Ours had a well appointed shower room with a hand-basin in the room. We had a view over the park, which was lovely, if a little noisy from the main road traffic if you opened the window. Wi-fi access (free) was initially temperamental but sorted out. We did have an issue with next-door's fire alarm in the middle of the night, but that was hardly the fault of the establishment.
Breakfast is reasonable though not lavish, with eggs (only) individually cooked by the charming staff, but there were ham, cheese and pastries available. There is an evening meals service which we did not try, as there are lots of good eateries in the vicinity (including the fascinating Bel Canto operatic dinners at the Corus Hotel a few doors away).
There is a small sitting-room/bar at the front of the hotel which doubles as reception and a small lounge; probably not the place to stay if you plan to stay in a lot during your stay. All staff were very welcoming and helpful.
The main value of the hotel is that the doubles are let per room, which brings the cost of the stay down for a London Hotel. Do not stay here if your expectations are of the height of luxury, but as a comfortable, clean place to stay in London it is great.