Stayed here for one night on business, choosing it purely for location/proximity to the rail stations.
This is supposed to be one of the premier hotels in central London (famous for it's courtyard restaurant). It is extremely well appointed with meticulous, serene public areas and very helpful staff. It's a traditional 'railway' hotel, purpose built - so the rooms are spacious etc.
If your'e walking here, the hotel is on the far side of one of London's busiest roads (so not a pretty locale) and it's approximately 15-20mins from Oxford street (shopping) and next door to Marylebone station (for the tube). The entrance to the front of the hotel is via narrow taxi lane...which seemed rather precarious.
Check in was smooth and I was given a room at the back on the 3rd floor - a long walk from the elevators. First impression when getting out of the elevators was the very, very strong smell of cigarette smoke. It's illegal to smoke indoors in the UK but some hotels are allowed to maintain rooms for smokers (a legal loophole). Which is frankly ludicrous as is in this case the smell/smoke permeates through the entire floor. Regardless of any other aspect of the hotel this was enough to make me think 'never again' before I'd even reached my room.
The room was huge and spacious, almost to the point of being silly. Seemed very clean and well appointed. Bathroom was enormous and probably needed some furniture to fill the huge floor space. The decor is not cutting edge and perhaps even a little dated. It's a regal style they are going for with lots of heavy fabric and dark furniture. The bed was super comfortable and importantly the room was quiet despite being above the station.
I didn't eat in the hotel - plenty of great restaurants on Baker Street. And didn't have time to use the gym etc. But as mentioned my entire impression of the property was dented by the stench of cigarette smoke and so wouldn't return.