I think the pool hoppers are back.   

My payout variance has been too high lately. Also I noticed by scanning their bithopper forum post that they seem to have found a way to hop here and at BTC Guild.

I did not spend too much time reading, but seems maybe they are using lp data and irc postings to determine when to hop.

I think slush is not effected as they have a different method for paying (as in you have to stay pretty much for the whole block).

This LP "who solved the block" procedure exploits an assumption, that a pool that finds a block will be sending notifications to miners earlier than other pools. This may not always be correct.