I don't have a ton of experience with boards but I do own both of these.
I went from the SB to a Westmark. I love my Westmark. I thought it was much more playful and snappy off the jumps. I'm doing more park but I'm an old guy so I may not be the best judge. I just know I liked it better.
I ride hard packed Midwest so not to much different than the east coast stuff. Sorry I didn't give a more technically detailed critique but hope it helps in some way