We had a 10 hr lay over at Heathrow (between two 10 hr flights) and needed to arrive at our final destination in as good shape as possible.
Yotel was easy to book, clean, friendly, convenient, private and restful. The beds were comfortable and we were able to freshen up and take a long nap. Location made all the difference since we didn;'t have to leave the airport so most of our time was spent relaxing (vs trying to get to a hotel outside of Heathrow).
I wouldn't hesitate to do Yotel again. It helped us to start our vacation without being totally exhausted.