Have they been up to see me? I have the Hitzer 710 and Keystoker Koker sitting side by side in my showroom.
Quick run down of the biggest differences based on my experience:
Hitzer 710 Keystoker Koker
BTU Rating 150,000 160,000
Hopper Capacity 160lbs 240lbs
Hopper Material Stainless Steel Galvanized
Standard Thermostat Coal-Trol Honeywell T-87 (but Coal-Trol is an option)
Convection Blower CFM 1,000 1,500
Venting Options Chim or Power Vent Chim or Direct Vent
Price $2800/ $3400 $3250/ $3600
As far as the quality of construction, I'm not going to take a line that manufacturer's junk. With that said, both of these units are amazing. I have easily sold 10+ Hitzers this summer and just as many Kokers. Both companies have been around for a long time. Obviously, the 710 is fairly new with it being the 3rd season available, but we rarely have issues with either. Hitzer had a minor problem with the wiring on the Coal-Trol but that has all been resolved. I guess the biggest place we separate our customers on these furnaces is the size of the house, the length and setup of the duct work, and how it will be vented.
Matthaus commented towards looking into the Leisure Line. I have been trying to gain access to that line, so I can look into how they're built and we've expressed interest with our distributor over the last year into possibly carrying the line. However, we've been unsuccessful with it so far, as there is a dealer pretty close to me that sells them. Of course that dealer doesn't sell coal and knows nothing about coal, annoying when they sell a furnace and I have to teach someone how to operate it because they don't have a clue! I've heard good things about Leisure Line, but with their lack of interest in setting me up, I'm not impressed so far.
If anyone has questions as to their specific application, I'd be happy to help!