We had a great experience at J.B.´s in London. The apartment is really nice and clean, well situated, 5 min to subway and well connected to Stansted airport. JB is a perfect host.
Just a couple of things to improve, the stairs and halls of the building until you get to the floor are really dirty and seem no to be cleaned in a while.
And a little more room in the closets would be good...

Spite of those things, we really love the place and will repeat when we get back