There has been a few threads on the ride of the decade and from the sounds of things, it is an all-around upgrade from the natural... like the Natural was from the player. but it is more than an upgrade, it's an all-around new shape not just an "upgrade"
here is one thread http://www.wakeworld.com/MB/Discus/messages/65919/626824.html
i have not ridden either of the boards, and i imagine the chances of someone having ridden two new 09 models to make a comparison is limited to none.
limited to the two i know i'd have a hard time choosing. PERSONALLY i think i might end up going with the byerly just because of the "flex" they put into the board (still not what i'd call a flex board though) BUT with your already established approval and love of the natural i think YOU might like the decade better.
just some thoughts, helpfull or not, there they are. ;)