I tried out my new Sigma 1000 grit Power Select II stone today for the first time, removing a fairly large nick from a PM-V11 plane blade. WOW, just incredible. The speed, and feedback on this stone is just fantastic.

This got me thinking about their finishing stones. I have Imanishi stones in 4000 and 8000. They do a decent job, even though they are a bit slow and dead when it comes to feedback. For those of you who have 12000 and 13000 (or even higher) grit waterstones, do you see a noticeable difference over 8K? If so, what in your experience is the difference?