Saying that his reign was better than The Rock's two months and Cena's current really isn't much. Punk/Jericho was only okay in my opinion and his MiTB match was atrocious. It can be summed up as terribly done spots and a very, very, very shitty ending. He didn't pick up any steam until he did his pipebomb shtick on The Rock and at that point he was about 3 weeks away from dropping the strap anyway.
In my opinion, JBL's reign of '04 >>>> Punk's. Punk was definitely one of the best champions in recent memory, but only because he held it for so long and gave it credibility that it lost somewhere between 08-10. It's nowhere near as legendary as it's made out to have been, that's all I'm saying.