Front brake. I was dubious at first being accustomed to two brakes on my road bike, but it works fine for me, especially since installing Koolstop pads.

I tried brakeless for maybe two rides on MUPs at first but decided it was borderline suicidal. (Edit: Plus, being used to riding on the hoods, it wasn't comfortable.)

Being older and protective of my knees, I prefer not to backpedal hard or skid. Mild backpedaling to adjust speed is OK for me though.

BTW, got Cane Creek road levers from my wife for Xmas to replace the crappy old suicide lever stock ones on my conversion.