I stayed here last summer before it joined Hilton and want to add my thoughts for anyone considering it in the future. My wife and I loved this hotel - admittedly it was not a Hilton at that point but I assume much of our experience would not be affected by the change. The location was a little quiet at night, but we were there during the riots so that was a MAJOR plus. Putting that aside, we liked the location as first time visitors. As relatively young and fit people we walked up to Parliament, etc quite easily. The tube is not too bad of a walk in the other direction as well. If you are looking for nightlife, this is not the place. But for a touring trip or for families, I think the location can be quite good.
The service was also terrific. My wife took ill one day as she was pregnant during the trip and the hotel was responsive and kind. The IMAC was an interesting/cool touch and the room was quite nice. We chose the hotel b/c of good TA reviews and an exceptionally low rate available through an OTA and we were extremely pleased.