I have 2 of those guns, one in .300 Win Mag, and the other in .308 (the .300 is called Sendero SF, and the .308 - same thing just shorter action - is called Varmint SF).
These guns are very big, bulky, and heavy. However, they shoot great. My .300WM has a Nightforce scope mounted on it, with Warne HD SS rings, and customized by AnswerProducts with a special muzzle brake and recoil pad. The gun weighs about as much as an anchor, but I don't care because I use it still hunting.
Given that Remington doesn't offer this gun in .338 RUM anymore is something that you should note. The RUMs are all but dead (I own one in .300 and the other in 7mm) and I am regreting it now.
The .338 RUM would make for a true long range big game rifle - like elk. However, there is no way in the world that I can see anyone carrying an "anchor" on an elk hunt, where you have to walk alot, and at higher altitudes. Your best bet there is probably a lightweight Kimber Montana in .300WSM (of which I also own, and for said purpose).
Zachary