Salsco
I used to work for a company in NC that was a Salsco dealer. I have been in or around the tree business for 10 years, and either worked on or sold equipment for 20. Currently operating a family biz and climbing full time, so I really have no dog in this fight.
I learned a lot about chippers while selling Salsco. I sold a few to municipalities before leaving that job and all were totally satisfied. They are built like tanks and sit on the stoutest frame in the industry. They also utilize 2 bed knives, which makes for some nice chips. There is also a large slot behind the blade pockets on the disc that greatly increases the ability to exhaust chips. I spent many hours with the model 813 and never clogged it. On one demo, we chipped dead, wet, rotten wood mixed with honeysuckle vines. The customer was trying to clog the machine as his Bandit was notorious for this. The Salsco never slowed down. Their speed sensing also runs off the chipper disc, not the engine. No more smoked belts, and a faster "catch up time" with big wood. The machines are hand built, one at a time and the fit and finish is far better than anything else we compared it to. Machine is powder coated before assembly, so no unpainted surfaces mated together or painted hyd hoses. Sal (the owner) builds one hell of a machine.
The down side is, of course, the price, but you definately get what you pay for. Our company currently uses a Vermeer chuck and duck. We looked into buying a 13" Salsco, but just can't justify the price vs the benifet of a large chipper. 90% of our business is wrecking pine trees and we rarely chip anything larger than 6" (log the rest).