I use a Dremel with cut-off wheel on my own brake cable housings at home. Always square and clean, just need to go slow to not melt the liner closed! A Trek-branded cable cutter works fine on cables and shift housings.
At Bike Works where there’s no Dremel available, I’ve been impressed with the clean cuts from Jagwire cable cutters there on brake housing. I’ve never like the dang curled-in end that always results from using the Park cutter on brake housing, so I’d used the largest, sharpest pair of diagonal cutters for better results, until I found the Jagwire.
I always flex brake housing in a tight bend over a finger and work the cutter blades between adjacent spirals for the best cut with any of them.