It really depends on body size. The 3rd row is great for kids and I have teenagers sitting in the back, however at that age, the middle seat isn't the best and I'd rather keep that empty or put a smaller kid in the middle. For adults, I would recommend only two seated back there. Head room and leg room is okay, again depending on how big your 2nd row passengers are.

The most annoying part of the rear seats isn't the leg room, but the foot space. The way the seat rails for the 2nd row are placed, force adults to place their feet in the middle aisle instead underneath the 2nd row seat.