There is a nice video on YouTube comparing a Brompton, Birdy, and Ori (classic frame, not the new curved frame):
http://www.youtube.com/watch?v=A8TQHBdUTmk . Notice that the Brompton has the smallest volume when folded (86 Liters), Ori middle (135 L), and Birdy the largest (173 L). Another thing that caught my eye was that when the Ori is folded, the front wheel is disengaged from the front fork, leaving the fork and its dropouts precariously exposed to being bent if it is roughly handled in transit. If I had an Ori (or Mezzo look-alike), I would put a dummy axle of some sort into the front dropouts when the folded bike is in a bag or box being shipped or carried in a bus or train.