Choice of row cleaners should be based primarily on the typical tillage and residue conditions you are planting into.

If you typically no till all your corn into bean stubble, then unit mounted floating row cleaners as pictured above may be your best choice.

ALL row cleaners need to be adjusted now and then, even the lower stop on floaters.

Floaters lose the stretch/cut action so important in longer, tougher residue.

For most 4/6/8 row 30" JD 7000 applications I find a simple face plate mounted, screw adjust fingered Trashwheels, set in the offset (non intersecting) position is the lowest cost, most flexible and overall best choice for most 7000 customers.  

Jim at Dawn