I have never shot the 270 WSM but I can't imagine the recoil to be that much more than the 270 Win. I have on the other hand shot a Winchester model 70 Wal-Mart special in 300 WSM. To me the recoil in that gun was considerably less than a 300 Win Mag. That being said I would still go with the 270 win. My main reason being ammo selection. If you compare the two although the WSM will outrun the Win you have a much broader selection. In addition to that 270 win can be found at just about any mom and pop store that carries ammo.
I'm really not one to talk though considering that I have a Tikka T3 in 338 Federal. Out of 3 gun stores and all of the Wal-Marts around only one of them carries the ammo. My solution is just to keep a good supply handy and don't forget them when I go hunting away from home.