This last N increase has hit my CPU mining hash rate hard, around 42%. It would be interesting to see how it hit GPU mining to see if the algorithm is going in the right direction.

I'm a bit concerned that N might be getting too big even for CPUs though. My single core EC2 micro-instance was capable of mining (at a slow rate) before the N increase, but now it's pretty much unable. Wondering what the rest of N increases might cause, perhaps the pools need to start adding variable difficulty to cater for slower CPUs or the next N increase might kill a good amount of lower-end ones.