I think the reasons why people mine without a PPS pool (especially PROP) are very simple. One part knows what they are doing, another big part probably not, and a small part does not give a shit.

In my opinion it is reasonable to exploit others to get the most benefit for yourself, so I dont really blame anyone who hops pools frequently. If the possibility for exploiting exist you can expect that some people will do it and others will follow.

However, from the view as pool operator it should be primary target to make regular miners happy and give them the best possible value, so the only solution for this is PPS in my opinion (there cant be any better method, and no method is fairer). That's why I have implemented PPS in my pool now too and users can choose if they want to mine with PPS or PROP. Although the payout is not instantly I dont deem the payout scheme to be worse than PROP payout as soon as a block is cleared and credited.

We save all the valid PPS shares (along with a timestamp) in a queue and credit them one after another to the user as soon as the pool balance can allow this. Basically this means every time a block is cleared and credited, the next time when the queue will be checked, it will credit PPS shares to users until there is no more balance left. So it might happen a couple of times, that you cannot cash out your rewards instantly, but on the other hand it can also quite often be that you can cash out your shares before a block has been cleared.