The apartment is at a nice location near the Kings Cross station, the staff is very kind - we arrived to London before our check-in and they let us leave our luggage at reception until then anyway.
One thing that bothered us was cleanliness - when we arrived, the bedsheets, pillow covers and towels were all dirty. Even though they later replaced them it still gave a very bad first impression and overall feeling after that. The bathroom is also quite a mess, the shower head and faucet are both in a pretty bad shape as well as the toilet cover which is all sorts of messed up.