Hey W. Jones.....
I can say that the Woodland Mills WC 68 has met my expectations. By now, I have probably logged about 15 hours on the machine with a variety of tree species.
It depends on what kind of tree limbs/brush/green/dried/ crooked you are feeding the intake. As you can imagine, straight green limbs feed quite easily. Currently I have been chipping dead dry cedar limbs that are rigid and long. Sometime I have to wiggle the butt end a bit for it to grab hold. Same is true for the bushy rigid stuff. It's still work on these hot days, but I am satisfied. The reverse hydraulic usually releases the source of a jam, and one just moves right on again.
Cheers,
Mike