Usually we give the customer some credit back in exchange for the steel and holder. We then sell them the Tuuk and any steel of their choice at cost and charge a very minimal fee to mount.
While Tuuks are still more popular than the Step/VH holder, we are starting to see more people switch to the Step/VH holder on other brands of skates, specifically a lot of people who use CCM and dislike thr SB holders.
Personally, I love the Step/VH holder. My main issue is no one other than Step, and soon to be Tydan, make steel for it.
In the end, it's likely I'll be using the next generation CCM holder when it releases soon. I have been very impressed by it so far.