Make the decision based on weather if possible. Check the Drive BC website before leaving.
Given similar weather on both routes Hwy 95 through Kootenay Park has much longer and steeper hills than does the Crowsnest though that may not bother a professional. 95 also has much higher passes than does the Crowsnest so there may be more accumulated snow.
The drawback of the Crowsnest can be very strong winds getting down to #3 from Calgary and the possibility of blowing snow and very bad visibility in the pass area.
We have towed both routes many times but not in winter.