While I don't own a 6.5 PRC, I've rebarrelled my 6.5-284 Norma twice(built on a long action). Awesome round. Tack driver and virtually no recoil. I shoot the 140 gr VLD's or the 124 gr Hammer Hunters in it. It's a great deer and pronghorn cartridge in my opinion, but I prefer a larger caliber for elk. That being said, I just built a lighter weight 280 AI. It does have more recoil than the Norma, but it's really nothing. Very accurate cartridge too. Both rifles have muzzle brakes.
My feeling is the 280 AI is more versatile than the PRC. While you're at the limit for bullet weight with 140-156 gr bullets in the 6.5, you can load down to the 140's or up to the 180's in the 280 AI.
My choice for elk is either my 300 WSM or 338 Lapua. Not to say the 280 or PRC couldn't get it done, but I've NEVER wished I had less firepower. Had a friend come to this conclusion after getting his first elk with the Creed. He told me he wished he had something with more "thump" and should have borrowed one of my larger caliber rifles.
Now, I rebarreled my Tikka from a 243 to the 6.5 Creed recently with a 24" Proof prefit. Didn't think I'd ever get on the Creed bandwagon, but I love mine. Crazy thing is I can attain close to 6.5-284 Norma speeds with the 143 gr ELDX and RL26. I get 2959 fps in the Creed, while I get 2997 fps with the same bullet in my 6.5-284 with Retumbo. Has me questioning if I'll keep the 6.5-284 or not.
Either way, you really can't go wrong. Look at ballistics & bullet choices for both, and see what works best for the game you plan on hunting. I've rediscovered my 30-06 this past year, and I could hunt everything with it if I could only have one rifle.