I've had, and have, discs. I really don't see what all the fuss is about. First bicycle rim brakes are discs...just ones with really large rotors. Second, braking is much more than just how hard you can clamp the wheel. Every brake I've owned (with the exception of some centerpull brakes) are capable of sliding the rear wheel, even with a touring load and me hanging off the back of the saddle as far as I can. That's the limit (almost) of how hard you can brake a bike. Moving the center of gravity of the bike, i.e. the rider because we are most of the weight of the system, back and down does more for braking power that any brake system. Even in adverse conditions.

And having very powerful and touchy brakes in adverse conditions isn't necessarily the bees knees, either. If you slide the front wheel, you are going to be on the ground. Not much can stop that happening. On ice, you want to have a very light touch to avoid that. In water, you still need to have a light touch, just not as light.

But the type of brake is moot in your case because the Sojourn is set up for discs without an option for anything else. You has to dance with them that brung ya.