Re: 300RUM versus 7mmSTW
More options for brass if you go STW. Combine that cartridge with the 180VLD & you've got a serious hammer. That being said, I have to vote for the Ultra. You mentioned hunting, the larger cross sectional area of the 30cal boolit is going to provide advantages. With the new LR Accubonds, the new 215 & 230 Bergers & the new(ish) Barnes LRX, the 300mags are starting to show favor once again.
Recoil be damned, put a brake on it & forget it.