I had an equipment swap last minute once on a 777 to the US. It's not ideal, and compared to the Qsuite it's a real let down. The biggest problem with the old J is not having all aisle access, and having to possibly wake or bother your seatmate when they are in bed mode and you want to get out. If you end up having to take a non-Qsuite 777, definitely sit in the center seats so you can have aisle access. That being said, I can think of worst business class seats.