For me, I went with a PTO powered
chipper (manufactured by Bolens, which I believe is owned by Garden Way now). I don't use it all that often, and didn't want the maintenance associated with having another motor to take care of. It was also less expensive. My
chipper has a bottom exhaust (doesn't shoot the chips out of a chute) and is a manual feed. I bought it used last year for a real good price, and it has worked well for me.
Some folks worry about running up the hours on their tractor engines just to run a
chipper. Based on what I've heard and read on this forum, there are very few of us that will ever put enough hours on our machines to worry about wearing them out.