It's just a matter of what you WANT to shoot. The 300 WM probably has more than sufficient energy and distance for anything you might want to hunt. Brass is cheaper, more plentiful and you can buy better quality brass than you can for the 338 RUM with which you'll be stuck with using Rem brass so you may find it easier to get better accuracy out of the 300 WM. Bullets are cheaper too and it burns a little less powder. There's nothing inherently inaccurate about the 338 RUM or the Edge and very good bullets are available but they do cost more, quite a bit more, to shoot and they have noticeably more recoil. What it really comes down to, if you don't consider expense, is what itch you want to scratch.