I once used a small electric Black & Decker shredder/
chipper. It was okay for the small stuff I had on our 1/3 of an acre in NJ.
In Baton Rouge, the house came with an 8 hp Troy Bilt Tomahawk. That thing would do up to around 2". Got lots of exercise bending down and poking stuff into it and even more exercise going through numerous rotation of the hammers and sharpening of the
chipper blade. That thing was an absolute beast to maintain.
Have a MacKissic TPH 122 on the PTO of my 18.5 hp JD now, and it's great. Paid about $1,800 for it. I got it from my JD dealer. You can get them from MacKissic and from the DR folks. It's a dream to maintain compared to the TroyBilt. On the TroyBilt, the spacers between the hammers would get totally messed up and required a lot of hammering to get the shafts out. Also, the little keeper pins were a pain to get out first. On the Mac, the keeper pins come out no sweat, and the shafts just practically slide out. The spacers don't get beat up and require replacement. Removing the
chipper blade requires a good allen wrench of the right size and cleaning of the allen screw depressions, etc., but once you get that technique down, this job is easy. The Troy Bilt had bolts on the
chipper blades. Getting a wrench on the back side of the bolt required some contortions but not near as bad as laying on the ground, etc. to pound those shafts out to rotate the hammers (they have 4 corners; only one corner "grabs" stuff and eventually gets rounded off).
I've seen some of the little units where it was virtually impossible to insert trash branches straight into it. The chute had a severe curve, undoubtedly to keep fools from putting their hands into them past the curve. The curved chute made them virtually useless.
Ralph