I went with the 163 and am very happy with my dicision. IMO it really depends on what the snow is like where you ride the most, I ride mostly in Golden B.C. and Revelstoke, luckily we get quite a bit of fairly light fluffy powder. I like to ride in the trees and am not good enough to go too fast so I find that the extra track allows me to go a bit slower without getting stuck. It is a fairly subtle difference, I am also 215 Lbs, so need to spread the load over a bigger area. If I lived in a costal area where the snow was heavier and I was lighter a 154 would probably be the ticket, hope this helps.