Go with large. For some reason Burton always runs small!! I wear a size 11 snowboard boot, ordered size 11 Ions....too small needed 11.5. Bought a pair of med P1.1's too small....the mission large adjust nicely. GO LARGE OR GO HOME!!!
get the large I just had to replace mine because I thought a size 11 would work with medium bindings that I already had( hey thats what the sizing chart says) Rule of thumb with burton anything over a 9.5 go with a large.