As Anne noted, the Paddington Hilton is great for access to the Heathrow Express, since the hotel is in the same building as the train station. One simply goes down the escalator from the hotel into the train station and onto the Heathrow Express. Marvelous, indeed. Paddington is also the station from which one takes the trains to Oxford (from which one can get a bus to Woodstock to visit Blenheim Palace, the birthplace of Winston Churchill and one of the great palaces of England). The Paddington Hilton is quite modern in decor and facilities and had A/C that was about 7 degrees cooler than that available to Kathy & Frank at the much more expensive Intercontinental Mayfair. There is also a major Underground station right in Paddington Station, thus allowing easy access to almost anywhere in London. So, if one has Hilton points to use, the Paddington Hilton is a good choice in London.
Cheers, Fred