Hyatt - better uses globally, London properties not best

iHG - won't go wrong with IC Park Lane at bargain 50k

Carlson - The May Fair is their poshest hotel, perhaps globally, but it is a bit W-ish and overbusy. They also have a couple of bad shoeboxes they give out on redemptions if you have no status. Park Plaza Westminster Bridge is new, great location for tourist stuff and has a pool.

SPG - W is the best property with tiny rooms, rest are forgettable

I would go IC Park Lane or Park Plaza Westminster Bridge.