Cory I've ridden both, I would say that the S4 is faster, and has more grip than the watson, but you can still break the s4 loose very easily. The S4 is locked on edge coming in. As far as landings, they are about the same. I noticed a big improvement on my toeside pop on the S4 and my riding partner has the same board and he said the same thing. Both pop really well tho
Oh and I have a 09 S4 138 I'd cut you a deal on if your interested, i rode it for a couple months last season, great shape.