Stayed at the Radisson Blu over Christmas. Good location (although still a bit of a walk to V&A - though there is a free shuttle), beautiful hotel. But the customer service was quite bad. In particular, the manager with the gap tooth was quite patronizing. I inquired about something that another manager said they would consider for me, and would call me to give me a response. When I did not get a response by the next day, I inquired about it at the desk, where this manager immediately dismissed me with a bit of a smirk. I tried to explain to her what had happened, whereas she then misquoted the hotel group's policies (she claimed upgrade were only if available, and it was up to the hotel to decide if upgrades were available, instead of basing it on inventory), and told me that they of course would not offer free breakfast to me. She talked over me when I tried to explain the situation. I returned to my room, but 5 minutes later she called and said actually the management had already decided to give me free breakfast the day prior, and sounded surprised by this.
That was just one event. In general, I did not find the hotel to be particularly service-oriented. They were very busy, but they should not be so impolite.
That said, wonderful hotel if you do not have to deal with the front desk.