It is similar to a PPS system, but at the same time it is not a pps system.  The queue is a lot more noticeable when you run it against coins that have a much higher buy price.  With NET being at a low price right now, there is basically no wait to get in the queue for payout as the minimum is 1 NET.  But if the price were higher and you were waiting for a while to get paid out, it ensures that you do not have to wait to get paid behind some big miner.  You are in the front of the list when the payout cycle starts once you have the minimum balance.