John has that "bad boy" energy.... (I've always had a certain attraction to that, but I know not everyone does.) He's focused on his agenda, and if you're not with him, you're against him, scholarship or no scholarship. Bobby, on the other hand, is more everyman, but there's a core of experience and wisdom to him. John may have experience---in more ways than one---but he's even admitted that he's not really wise, that he's just muddled through doing the best he could. Bobby presents a gruff, pragmatic exterior, but he also consistantly demonstrates loyalty, compassion and common sense. I think he's more reconciled to his path...I'd love to see backstory for Bobby next season, although it's sure to Joss everything I've come up with! John, though---paradoxically, as much as he regrets having dragged the boys into the life he's led all these years, I believe if he hadn't had to survive for them, that he wouldn't've lasted as long. Bobby is more self-contained, and again, I'm oh-so-curious as to Kripke's version of his background....