Bob Benson is Don with no code and no loyalty, running amok. As bad as Don has been, he could have been a lot worse.
That I can buy. As bad as Don is, he's not running around plotting to rob old ladies of their (believed) savings and then murder them. Bob Benson may well be a would-be murderer in the making. He must think Joan has money. I just don't have any faith that Don can reinvent himself in a positive way at this point in his life. Yeah, I'm cynical.
Peggy probably is
better off, but Ted's motives are born of weakness, not altruism. Nice that he came to the conclusion after he took Peggy to bed and not before. Lots of Teds out there. His wife will probably leave him in the future. That's the way it usually works.