Are you spreading dry, bed pack type material or loose, slurry type?
If it's a looser slurry like swine or dairy cattle, then you can't go wrong with a Knight Pro-Twin Slinger.
We ran them for a long time at the family dairy farm and they perform exceptionally well spreading slurry and most bed pack type material found on a dairy farm. The hammers process and distribute the product quite well and the hydraulic gate gives the operator very fine control over application rates. However, they do not spread high fiber, dry materials worth a crap.
http://www.kuhnnorthamerica.com/us/products-manure-spreaders.html
When we changed our manure handling procedures and installed a separation facility to process the sand and fiber out from the slurry, the resulting fiber was too dry and clumpy for the Knight Pro-Twin. After asking around, we switched to a Meyer Industrial rear discharge.
http://meyermfg.com/products/1-4/ManureSpreaders
It has an auger unloading system that pulls the material to the back and twin vertical beaters to evenly distribute the material. We've had ours for 5 years now and haven't got a bad word to say about it. We run used semi 425 floats on it to cut tire costs from running down the road. As far as performance, there isn't anything we can put in it that it can't process and distribute evenly.
The only repairs we've actually done are when an operator kicked the PTO on with the rear gate still closed. The spreader was heaped with dry fiber from our processing plant and it bowed the rear gate right into the beaters. It sheared 2 of the beaters right off the drive shaft and exploded the gear box. He knew the gate has to be open before engaging PTO; he just wasn't paying attention and drove all the way across the field running it at PTO speed with the gate shut.
The other repairs we made weren't to the spreader, but to our 4440. The Meyers' spreaders are heavy units and a bit much for the draft assembly on an old 4440. We broke the draw bar yoke twice. Never had any issues once we moved to a bigger frame tractor.
So, depending on what you're spreading, these are 2 great models that have held up exceptionally well on an 800 head herd dairy farm. The knight's we always traded out every 2 years, but we used to trade out all of our manure handling equipment every 2 years due to volume we handled. Since we put in the processing plant, we haven't bought another manure spreader since switching to the Meyer's Industrial.
