Just got back into town after a UK/Ireland vacation, and as part of that trip we spent 6 nights at the Andaz Liverpool Street on a reward stay using Chase UR points transferred to Hyatt GP.
We booked an Andaz Suite, and unlike most of the photos I've seen, this particular Andaz Suite was in fact a one-bedroom suite. It had a bedroom and a separate living/office area. The suite itself was on the top floor of the hotel; so like all rooms on the top floor that face the city, it has these small, weird porthole windows.
The stay itself was great. We were checked in almost instantaneously, and everything in the hotel was quick and efficient. We were interested in exploring East London this time around, but you can easily get to anywhere in London (or nearby to London) from the massive Liverpool Street station that's literally next door.
The area around the hotel itself is pretty much dead on the weekends as it's based in the London Financial district, but it serves as a great jumping off point to get anywhere easily.
What I particularly liked about the Andaz were the small things that the hotel does to make the stay that much better. Some examples include: larger than normal toiletries, free wifi and non-alcoholic beverages from the mini-bar, nightly turn-down service, flashlight in the closet, plug adapters for foreign visitors, etc. It was this bulk of little things that made our stay that much more enjoyable. ^
As other folks have noted, the rates here tend to skyrocket during the week as I guess they cater more to business travelers, but I wouldn't hesitate one bit to redeem Hyatt GP here. I'd definitely make a return trip.