Strong endorsement for hi-tops. The ankle support did considerably reduce cramping in the back foot and make it much easier for ever so slight but massively relieving foot adjustments.
Started out with NikeSB low-tops. Foot cushioning was great but lots of cramping and difficulty doing slight foot adjustments.
Also, some food for thought. Am finding that these boards are really made for carving, not straight line-ing. Introducing even a slight carve into my riding did a lot to reduce cramping further.