I just went through this as well (see thread in this same section titled Deciding on a new big game rifle) and what I realized is that a lot depends on what you are looking for and the amount of shooting you do. If you do a lot of shooting, you probably want to stay away from the RUMs as the barrel life is shorter. Also, if you do a bunch of shooting, you can get used to dialing in your scope for each shot. I personally decided on the 300 RUM because I don't shoot that often and have not gotten to the point of adjusting my scope for shots (yet

). I also plan on reloading my own loads, so that will cut down on some of the costs. Just throwing a few things out there that I picked up to help you make the best decision!
If you do see my thread, check out the link in there to Broz's loads. He has put together one impressive 300 WM and is having great success with that.
Good luck!