This is fastly becoming my favorite tool in the shop. I use it to set up everything anymore and test cuts are a thing of the past. I really like it for setting up my rail and style bits so I tried it with the jointer blades today and it worked like a champ. I used to dread changing the jointer blade out but this made it as easy and as accurate as could possibly be done.
http://www.wixey.com/heightgauge/index.html