1) 1mm wont make a difference.
2) waist width is irrelevant due to the fact you dont place your feet in the middle of the board.
3) once binding angles, binding placement and side cut are all factored in, it will come down to splitting hairs when comparing the widths.
4) it also depends on what you want out of the board and what style of riding you enjoy. both are 2 completely decks.