The Langham London
Stayed - 2 nights, December 26-28
Upgrade - Booked the lowest Superior room, got upgraded to corner Deluxe room but the view was meh (overlooked the Pizza Express on Langham Pl)
Early check-in - yes. This was a godsend because there was a toddler in the aisle next to us who wouldn't stop crying/screaming for the entirety of our trans-Atlantic flight. We got to the hotel at around 10:45 am and the upgraded room was ready about 30 minutes later. We pretty much just slept the rest of the day.
Late check-out - yes, they proactively asked and used it.
Breakfast - buffet at Palm Court or à la carte at Roux. We only ate at Palm court
WiFi - Included
Amenity - $100 USD hotel credit on F&B, Spa, etc. We used it for Boxing Day afternoon tea at Palm court and it to converted to a measly £69 (the going GBP to USD exchange rate was about 0.74 - 0.77)