My first priority when choosing hotels is location, and this can't be beat. Amazingly convenient from Heathrow via Piccadilly line to the Green Park tube stop, and effortless walk (even with luggage) to the hotel door. However, being that the tubes in London are not air conditioned, we were sweating sitting in the hot train and from carrying luggage up the tube station stairs. The hotel lobby is barely air conditioned and the rooms aren't much better. On first inspection the room was very clean and there was enough space for four people. However I then noticed the dried raisins and potato chips on the floor near one of the beds so I can't say it's really clean. The wifi was only free b/c of my status w/ IHG.
Again, the location can't be beat... down the block from The Ritz, on the same block as Funky Buddha and around the corner from Mahiki, walk to major sites such as St James & Buckingham Palace. But, there was no "do not disturb" sign so my son made his own. The lobby was the size of a guest room, and there was no ambiance whatsoever, in any part of the hotel. Would I stay again, no. I'd find another place w/ a great location and more atmosphere.