PPS pools
Proportional. PPS is something else entirely.
In my opinion, the near-perfect analogy to pool-hopping is a game of poker where some people know the odds and the others don't. The ones with the knowledge (who put it to use) have a clear advantage.
Similarly, in both cases, the more people maximize their expected value by playing the odds optimally, the less there is to win. Ultimately, if everyone pool-hopped, the PPS pools would simply halt and the EV would drop to 0.
So it's not like Poker at all. You can still play poker if everyone knows the odds, you can't mine in prop if everyone hops.