I have been using generic brand sandpaper, 3M sandpaper and some cheap Chinese sandpaper to sand some pitting out of a Solingen blade I have. The difference is VERY noticeable, as I was sanding some corrosion off the blade with 80 grit Chinese paper the cutting speed was quite significantly reduced, about half an hour of sanding has failed to remove 50% of it. While the generic brand paper would remove all of it in 20 minutes or less.
My question is: What is the "best" sandpaper out there in terms of cutting speed?