considerably so, from a "average" view. both of these boots have a flex of 85 which is relatively soft. because the spk's have more padding everywhere, less of the power you put into your boot is transmitted to your ski, and it may feel loose or not all that responsive compared to a stiffer boot, or even the foil. spk's are specifically made for park. as for the foils, i've never ridden them, but i have xwave 8's which have a flex of 85 and i love them everywhere. good for everything. if you go outside the park more than 30% of the time, i'd reccomend foils, but keep in mind that not i nor many other people that have posted have ridden both boots and therefore, you should go out and try them on your own.