I have owned this sharpener for several years.  I use it to sharpen my 15" planer knives and 8" jointer knives as well as my chisels and hand plane knives.  I have the 4000 grit stone as well as the 1000.  I get excellent results and the 4000 grit stone creates truly a razor sharp edge. Yes, it's messy.  Yes, there are some plastic parts that are a bit cheap and flimsy.  But bottomline: it does a very fine job for me.  However.... and a BIG however...... Makita does not make a coarser stone.  Highland Hardware offered one for a while, but it has been discontinued.  Taking the dings out of my planer knives takes a VERY long time with the 1000 grit stone.  I messed up and put off buying the Highland stone.  So, the 1000 grit is as coarse as I can get.  PLEASE Makita, pretty please, offer a coarse stone!!!