I think this mainly depends on what else you've got in the cabinet. The 7 PRC has the best external ballistics due to its higher BC and muzzle velocity. It also has significantly lower recoil than the 300. All of this should translate into a very shootable LR rifle with excellent external and terminal ballistics.
OTOH, I replaced my 7mm RM (previously my primary and most powerful hunting rifle) with a 300 PRC and a 6.5 PRC barrel. Have the more powerful, higher recoil barrel for elk and moose and the 6.5 for everything else. If I were you, I'd be looking for a reason NOT to choose the 7 PRC. Seems to me it's the best LR cartridge with factory ammo support available. I've never had a 300 magnum, which was one reason I got one, and I was also convinced by those who claim it has better terminal performance than 7 RM on elk. We shall see.
This fall, I've got a bull moose tag here in Alberta. Though I plan to use 225 gr ELDM in my 300, since I expect my shot to be less than 200 yds I'm planning to use 190 gr CX if they shoot well enough in my rifle. My only reservation with the ELDM is hitting heavy bone in a large bodied animal at close range at high velocity. I think it's an excellent long range bullet for hunting. I also hope to take a whitetail or 3 and test out the ELDM on them. I've only taken a pronghorn with an ELDM so far and it worked well, but everything I've read and those I've talked to with more experience with them have had good performance. Like I said, my only concern would be at close range where you might need to take a quartering shot on a big bodied animal.
Following with interest, enjoy hearing about people's real world experience.