My hunting load is Winchester silver box 150 grain loads. The gun likes them, and they are easy to find.
The 270WSM launches the 150 grain projectiles at the same speed as the 270 Winchester with 130 grain bullets. The heavier bullet will carry better, and is more likely to penetrate through for a good blood trail. The heavier bullets in a magnum are also less likely to damage the meat.
Most of the points brought up in a 270-280 comparison would apply just as well in a 270WSM-7mmRM comparison. They both shoot a 140 grain bullet at the same speed for example, according to the Speer manual. The only additional difference is that the WSM case is for a short action. - Otherwise, it's the 270-280 debate, all over again.
I find that the 270WSM will do everything that is normally done with the 7mmRM, but with less powder and less recoil. A very pleasant, very efficient and effective round.