I wish my Brompton had disc brakes because I have a steep descent (~ 1/2 mile) on my commute that I am able to reach speeds up to 30mph rolling. When it's wet/damp, I'm on the brakes the entire time and the rims get quite toasty. Also, I don't like the fact that the dirt and grime is just wearing the rim/brakes when the water kicks up. I'd rather replace rotors/pads than rims.