270WSM... no contest!
The Short Mag has nothing but advantages over the standard calibre, and no disadvantages!
Shorter stiffer action in most rifles, which allows for better accuracy and a lighter rifle.
I reload for both and on average I get 150 fps faster with most loads... 200 fps with the 130 grain.
The recoil difference in rifles of equal weight is negligible and the difference in trajectory at long range is significant, especially on smaller game like coyotes and wolves.
Ammunition availability is equal and the short mags outsell the standard calibers in most areas and have for quite some time!
I'm serious.