I recently flew ORD-LHR in 8J. Good leg room, easy in and out, even with your seatmate reclined.

Strange thing though. I was in 8J both ways. On the outbound I could stretch out my legs and my feet would just go flat against the bulkhead wall. On the return I stretch out my legs and can barely reach the wall. At least a 4 to 6 inch difference. Unless I shrunk in London, the seat spacing changes from aircraft to aircraft.