When I was pricing them they were slightly cheaper per blade than the yetter unit, that was before crustbuster was involved. I rent a 40 bar from a distant neighbor. It has been over a lot of acres and units seems to be in very good shape, he has replaced blade at least once.  I have used it on about 2000 acres on my farm and the only problem that I have encountered with the unit is a bearing going out on the closing wheels. I was told that there was some issue with the 30", but do not remember what it was. Bar is not set up for dry, I am not sure how well it would get the dry into the ground as slot is very narrow.

http://agassociatesales.com/DMR_Premium_Toolbar.html