I stayed in the London Metropole quite a bit last year because their location was very convenient to my client and to Paddington Station. Hilton had just acquired the Stakis chain but they were not yet integrated within Hilton Honors at the time. I don't know about the status of renovation right now, but at the time I felt the rooms were a bit on the small side; however this is fairly common for many hotels within London. Be sure to ask for a room in the newer section of the hotel; some of those in the older section were quite shabby and decrepit.
I also found the rooms to be on the stuffy side with windows that were hard to open and air conditioning that may have conditioned the air in some manner but it it did not include cooling it. This was a general attribute of the hotel; I must have stayed in about eight rooms over a few month period and it was all pretty much the same. This may be not a problem for you but it was somewhat unpleasant in the summer. After my first visit, I always made it a point to request a fan at the time of reservation and at check in.