Well first off, I don't own one, but I have played with one...I do shoot the 270Win. I reckon if I had to have just one rifle for hunting...ya, I know, hope it never comes to that!! I would probably be a T3 in 270 WSM. The reason I say that is b/c it's affordable, just about 100% chance it will shoot well, and that 270WSM should kill everything on the plains and in the mountains...and that's where I spend most of my time, oh ya, it's a light gun, good for walkin'.
Having said all that, b/c I'm a reloader now, I'd probably get it in 270 Win now, as the preformance is so close, the handloader can squeeze a bit more umphf out of the regular Win. Also the added fact that you can buy ammo at any hardware store in the country would be quite important for me.
The 270 WSM is hamstrung with the same problem as the 270 Win...lack of bullet choice...if the 160g max bullet weight doesn't bother you then your
fine...but the WSM doesn't fix that problem, it just makes it go a little faster.
Ok, coffee buzz is fading, hope that helps little.