I went with the Case 1530 unit a couple years ago.  I had been using a Hiniker 6000.  I could not get the trash to flow through the Hinker in the fall like I can the Case.  I like the fact that the knives, on 30 inches, have good front to back room and are not all in one line.  I do not chop the stalks before fall anhy.  Worked great last year.  Just a little plugging trouble this year.  All in all I think it will be a good machine for me.  I run a 13 shank machine.