Thanks, everyone, for sharing your thoughts.
One is the frame design, with the BB attached behind the seat tube; this makes for rather bad ergodynamics. I can't imagine why they did this. It can't be fixed.
Oh, that is weird. I had to look up again what a BB was, but now that I look at it, that must be uncomfortable to pedal. Oddly enough, I am short and really do like absurdly high handlebars, though.
And I just noticed the Schwinn may be much heavier than I'd thought --- a few sites say 39 and 40 lbs! I have a Schwinn hybrid that I'm very happy with --- aluminum, bottom of the line ($280 in 2006), bought for a summer in LA and I kept it because I was really happy with it, pretty light (30 lbs or so) --- but it looks like the Schwinn folder wouldn't be as nice.
I will look again at the Downtube and Carryme, and maybe go down to the bike123 people this weekend and try out some bikes.
Thanks!