Mark (R),
I long ago decided that heating a tank of water outside the building, on a winters' day, 50, 75, 100 feet or more from where I was working, made little sense when the heat could be provided much closer to the wand. Therefore not having to pay for something I did not want or need was a bonus.
Much of the noise of the machine is due to the volume of air that is exhausted - clearly a machine that produces less airflow will be quieter. The pump also contributes to the overall volume, but would I be as happy with a nice quiet Flowjet 100psi?
Whilst I agree that a solution tank lid is a requirement, I was happy to design one that functioned the way I wanted, and let's face it everything added to a product increases the final price.
I find that I am using the Recoil far more than I expected since its' performance exceeded my expectations of it. All machines are designed and built around compromises, so whilst there are elements of the design I am not happy with, I can understand the compromises that brought them about and cannot say that the design and engineering decisions were wrong.
In the final analysis what I require is a machine that performs its' intended function as efficiently as possible within the parameters of size, weight and portability - this the Recoil certainly does.
John.