Regent Palace is centrally located next to the Underground Piccadilly Circus station. It was very humid inside without any air-conditioning. There's a window that opens up, but it doesn't stay open without something holding it open, so it didn't help because there was no breeze.
Toilets are shared and located next to the shower facilities. To use the shared shower facility, you call on the phone and wait for housekeeping to knock on your door, provide you with a bath towel, and then escort you down the long hallway to unlock an unused shower. We waited what seemed like 20 to 30 minutes and called again before someone showed up. We tried to circumvent this afterwards by saving our towels and looking for an unused shower that wasn't locked.
We were feeling all sweaty just before the shower and still sweaty right after the shower. Having a private shower in room is optional for an extra cost, but all those rooms were booked when we checked in. Our room was older, dingy, and in need of a new paint job, with a sink instead of a shower in the room.
There's a hotel safe in the lobby, but losing the safe key will cost you dearly, plus they'll have to call a locksmith to drill a hole in the safe to get your contents out (something you don't want to do if you need to depart soon).
The elevators were slow, so we opted to use the stairs. There's a concierge, Nescafé, and Marco Pierre White's famous Titanic restaurant, lounge bar, and gift shop. Allow yourself half an hour for the check-out process, as there was quite a queue. Outside the hotel the immediate area was very congested with people day and night. It's not a location/area I would recommend to stay in, although it's easy to get back to on the night bus when you're out late.