Hmm, I use both brakes, but I have my front brake adjusted so that I can hit it as hard as I want to and I won't do an endo unless I move my body weight forward slightly.

But, I have the Burley 99.9% of the time, so I have to use both brakes or the rear brake will just wear out right away and only cause me to skid. Plus, I don't think I can do an endo with the trailer attached, but anything is possible, I s'pose.