Hotel Indigo Kensington, London has been one of my favorites for work trips. Let down recently with lack of A/C, but refunded everything without any hassel.

I actually find this brand very inconsistent (globally). Notably bad ones in the US:
- Chicago Gold Coast looks like a beat-up Caribbean all inclusive place (tacky beach theme)
- Brooklyn Downtown offers noting other than the room, all of which are tiny (but this one is more about the location)

Exception:
- Atlanta Downtown had really big and nice rooms and was decorated well but the bar was more dive-bar (again, I suppose it's more about the location)