I mentioned to a friend of mine that I was going to get a 338 Lapua and he said before you do shoot my 300 win mag first. At my age I declined.
I wen with the 300 wsm. I needed a light rifle for mountains. The only drawback is recoil. My kimber mountain ascent goes under 6 lbs before a scope. I have developed a very accurate load at 308 velocities for eastern hunting. Best of both worlds.
The WSM is comparable to its big brother until you get to about a 180 grain bullet then the bigger case of the 300 mag makes it clearly superior.