I've always found it humorous when players get knocked for putting up worse stats in the playoffs. It's not good, no, but these are the BEST teams they're facing. Of course their stats will be worse.
That said, Stabler obviously stepped up his game in the postseason. I asked an older co-worker just now (bias - is a Raider fan) if Tarkenton or Stabler was better, and he said he'd rather have Stabler, that he was a winner, and running around like a maniac doesn't win Super Bowls. So basically what todd said. And that's fine, maybe I'm wrong, I didn't see that guys play. But stats don't support the Stabler > Tarkenton argument.