In terms of their peak, I'd take van Persie 2011-2013. I think that Rooney only reached that level once in his career — in 2009/10, but he lost his form after the injury and never regained it (and we had lost the league to Chelsea and got undeservedly eliminated by Bayern in the CL). So yeah, definitely peak RVP.
It's hard to say about their talent, as their skillset was so different. We usually mean technique when we say talent, but Rooney's endless stamina and aggressiveness were also something he was born with, really. I'd still say that van Persie edges it because of his immaculate touch and elegant playing style.
If we're picking which one to sign as a youngster, then it's Rooney, no debate.