I have a 10hp Patriot Forester; 14 years of chipping in Washington where trees result in a pile of branches as big as a house. I have a few hundred hours of run time on this machine - typically 30+ per year. They still make this model with several engine options.
Takes 3" in the chipper (if the wood is dead straight - 2 inch realistically), 1 inch in the shredder. It has an outboard bearing (doesn't rely on the motor bearing for the outboard support). It develops a high vacuum and a baffle and 6 inch hose works well to suck up leaves. This machine is about as good as you get for the price ($1000-1200), and I can't get away with anything less. All my neighbors have long since parked their 5hp box store chippers
It takes me 8 hours to chip/shred what I can do in 30 minutes with a 12 inch chipper, but at $400 a day for 12 inch rental.... my time is cheap. My body is trashed though - quite a work out. If the wood gets above 2 inches I toss it in a pile for firewood - no point in beating myself and the machine to death.
I've repaired it many times... cracked housings (latest was about 3 feet of cracks and the external bearing fell out with 5 pieces of housing - I should have fixed it years ago...), blown outboard bearings, everything external eventually falls off etc... and... for each full day, the 2 knives need sharpening. Sharpening takes about 30-40 minutes for removal, sharpen and reassembly. Mostly it's just a slight touch-up on a slow speed water wheel, but the difference is dramatic. The 6 (?) shredding hammers are still in one piece. It will be interesting if one lets go.
Today... If I had a tractor or whatever with PTO, I'd buy a DR chipper... but my needs exceed that of a typcial yard.