PPLNS pool that only finds a block or 2 a month / week if they miss the big fee blocks
What seems to be easy to guess is that PPLNS pool with small hashrate that finds a block once in a blue moon will be the less profitable compared to large PPLNS pools (pool fees ignored), since the fees reward spikes only last for a few days or weeks at best, those small pools's chances of hitting a block during that short period of time are slim, while large pools will most certainly manage to hit a few blocks with handsome fee rewards.
But...the reverse is also true. For whatever reason the small PPLNS pool has only been hitting 1 block a month but due to luck it's only on some of the biggest fee days. At the 6.25 point per block fees are now a lot more important.
Even an hour or two apart can cost you 10%
Block 632,485 had 1.198
BTC in fees mined 14:50:58 UTC (Today)
Block 632,491 had 0.396
BTC in fees mined 16:21:25 UTC
Ouch.....if you were on a long PPLNS round and found 632,491 instead of 485.
But......WooHoo extra beer if you found 485 instead of 491.
And....whatever if you are on a large PPS+ pool.....
-Dave