Brompton caliper brakes need updating really, with q/r and barrel adjuster. Like any cheap caliper. It's a pain taking off a brake pad to remove a wheel.
I'm pretty happy with my Brompton these days. Switching from a 13t to 14t sprocket has transformed the drivetrain from grindy to smooth and it rides well overall. Anyone who is interested in Bromptons should just buy a second hand one and try it for a while (of course taking precautions to avoid stolen goods). My Dahon is nice too, around 6 years old and still going strong.