From what I' ve seen, the .270 WSM is the only considerable increase in performance of all the WSM/SAUMs, however, the entire line is an answer to an unasked question, we don' t need a 7mm or .300 that is 100-250fps faster than it' s predecessors, in any hunting situation, I guarantee that you' ll never notice the advantage. People may argue that now you get the same power from a short action, do you really notice the extra .75" draw on your bolt that much? I know I don' t, only time I slack or rip a bolt is when I go between a full sized .22bolt action to a small framed .30-06bolt moving from a 1.5-2" pull to a four inch pull, and that' s only when I' m lazy, it' s not that big of an advantage to use a short action, only when you consider you save a nickel per 100round in powder, but you' re going to pay so much more per brass or per factory round that you' ll still be paying extra.

It' s a bunch of hype, have fun paying half a buck more per round if you get one though.

I may be buying a .243WSSM this summer though, just to be hypocritical

I think the promotion is that in the same weight of rifle, the WSM' s give less felt recoil (although those #' s disprove that too), but then they chamber it in a short action, and short barrel, so you' d never know it was supposed to kick less. I don' t think they kick all that bad at all, but I' ve grown up with true big bores since I started, Super .45-70' s, .416 rigby' s, .458Wins and .458lotts, plus some sub-.40 " big bores" .375H&H, .338Win and Lapua, shoot big bores enough, and even mag 30cals don' t seem like much.