This weekend one of my old college buddies (who is 6'3 315lbs ex offensive lineman) rode in the backseat for a 2 1/2 hour round trip and proclaimed it "not bad with plenty of head and legroom" however he did say that the seat "scoop" was little narrow...but admitted that his backside may be a little wider than normal.
The best part is that neither of the front seats ever have to be adjusted forward when people ride in the back...and that's a first for me among many different vehicles I've owned. I've only been in the backseat once, and that was for a short hop while my wife was driving and her mom was riding shotgun....but I also thought it wasn't bad, but a little noiser than the front.