In a couple weeks we'll have a new rear wheel built up for the TRP Spyre SLC / 200mm ICE 6 bolt. We'll share the experience. Based on our cross tandem with disc, I don't expect more "power" than the rim brakes, nor more confidence in descents to go faster. All our discs so far are mushy compared to rim brakes. But as we have several doubles with 20k climbing this year through the Rockies, and pretty tight time limits; it is a given we will be descending in the rain at some point. The Rockies rain 9 out of 10 afternoons from June to August. For those rides we'll swap in the wheel and disc brake (with a splice in the brake cable). I did not want to fret toward the end of 200 mile day heading down a mountain pass in the rain that I'm wrecking a rim with road grit or have any loss in brake ability on a wet rim.