Before - John Raper?
Since - Brad Clyde?
John Raper himself told Pricey to take a breath and slow down due to Pricey's work rate and omnipresence on the field. He felt that a player that never stopped like him would just burn his career very quickly. See in Rapers day a lock played more of a roving role and a cover defender. Not the balls all in type of role Pricey was exhibiting.
Bradley Clyde was the closest thing to Pricey, but I put Pricey slightly ahead of him due to a couple of things. Clyde started of with a bang to some extent but started to deteriorate badly midway to last 3rd of his career due to injuries. He also was playing in a team that had an all international front row in Glen Lazarus, Brent Todd and Steve Walters. Pricey never had that calibre a front row in his whole career to spring board off.
Having that front row of pure power and creativity can never be underestimated and what that then allows the rest of the pack and team to do.
Also I put Pricey in front on mental will, tenacity and single bloody mindedness. That 1986 GF he willed us to victory. If he wasn't on the field there's no way we win that game. He was our Cameron Smith. Very few people had what he had if any. That was what gave him the will to play on even when he was a broken wreck. He played in an era that didn't have sports science or much medical help for many types of injuries so he would nurse himself back to health. Clyde started to play just as things started to get professional and medical treatments started to get better.
But anyway, Pricey in my opinion should be judged just like Raper was on what he achieved in his era. I mean does anyone seriously think that Raper could go out drinking all night, no sleep and then play a man of the match performance in todays RL? It was a different game back then as it was in the 70's and early 80's and then again from late 80's-90's. So it is impossible to accurately compare these player against one another. So the best we can do is judge them on their performances and achievements and Price's is as good as it gets for his entire career. More then worthy of being an Immortal. His influence on Parra is Camron Smith or Johnathan Thurston like without being a playmaker. Again not many players can lay claim on driving their club for more then a decade to successive finals and grand Finals and 4 premierships like he has.
Immortal? You betcha!