The one thing nice about Coaltrol is stove independant, you can use the same unit on Keystoker,Harman, leisure line and the newer alaska , anything with two separate motors can benefit from a coal trol, if someone is about to come out with a new stove that uses two separate motors, they can use a coal trol. But if you are to experiment, ( make a pizza oven, hot water heater, low end boiler ) it's not for you. You have addressed the other issue, and that is cost.
The Coal Pilot on the other hand , is very specific to the mechanism of the stove, at the time of the design, the inventor did not know that Alaska is phasing out the carpet feed, so his market is limited.
The unit built for the Leisure line, is very impressive design, it works extremely well, but most if not all leisureline stoves come already with a Coaltrol unit.
There is no Coalpilot for a harman, or a keystoker, but I do understand, there is a blue print design for both, but again there is no market demand to justify manufactring.
The other nice feature of the Coalpilot, is you can buy the spare parts separately, and very inexpensively,in case you need to do your repair. a standard carpet sells for 15 dollars plus another 15 for shipping from Alaska dealers, but a Coalpilot with laser drilled holes( for triburner ) is only 25 Dollars plus 10 Dollars shipping.