I liked how close the accomodation was to the train station, and that it was on one of the main lines, making it easy to get to anywhere we wanted around London. There was also bus stops right in front - we just didn't find the need to use them since the trains were usually quicker!
The breakfast buffet was also great, and I would recommend adding on as it was quite decent and makes your mornings easier.
Staff were friendly and helpful, and I liked that you were able to leave your luggage with them if you got there earlier before check-in, or needed storage until your flight later after check-out (most places would've charge you extra for luggage storage).
The only downside was that the room we had was a bit small, but it was still manageable as we were only there for a couple of nights.