I agree with Scott that anecdotally, the older your server, the better your neighbors.
I got PS service for the similar reasons to why the OP is considering it. I don't want to be beholden to the good behavior of my neighbors. Yes, Dreamhost will kick them out when they find these bad neighbors, but in the meantime my house will be wrapped in toilet paper.
I have very low traffic sites but I want them to be available when people do hit them. This means I can get PS but fit within the minimal plan, so it's not that much of a cash outlay for me.
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