Check out www.shortmags.org for bunches of info.
The WSM is slghtly fatter and longer than the rsaum, and gets just a little more velocity. The theoretical advantages of the short action over long are a few less ounces weight, a shorter bolt throw, and a stiffer action.
The shorter magazines (like on the Remingtons, HS Precision, and Brownings) may cause you to seat heavier bullets into the powder space. The magazines on the Winchesters and Kimbers are longer. Don't know about the Tikkas, Howas and Savages.
I think the WSM may outlast the RSAUM.
