Well, after having both and several 300RUM's, I would say neither. I burned out 2 RUM barrels. One after 1200 rounds and another after 600.
I have moved back to a 300win mag. I can get 3100fps with RL22 and 180gr accubond, but I could get over 3300fps with 300RUM and 180gr. And could get 3200fps with 300Weatherby.
I loved my RUM but it sucks to get a gun shooting well, and after a year of hard target shooting need to get it rebarreled.