I had one of those in my wake boarding boat and it worked incredibly well, even when we would hit double ups. I never spilled a drop. Also had a buddy with one mounted in his 40 and did a low speed flop. Drink stayed in and never even spilled because it simply rotated in its mount as designed.
Only two drawbacks that I can think of is that is has its limitations with insulated beverage containers and as stated above I can't think of a good place to mount it. I really want to figure one out because I am still amazed at the engineering that went into creating this cup holder.