How come Montague doesn't get into the discussion? I have a Prius, and it folds very well to fit into the back without limits. It's a full size bike and there are many positives over the others listed. It doesn't travel as well if you are taking the bus or train, but not everyone needs to meet those qualifications. Just wondering.
I say this, because I found a good deal on a brompton and bought it (amost a brand new bike, a 2010 M3L), and tho it is a work of art in my eyes, it doesn't compare to the Montague in purpose for me.