I bought the Oneida 5hp Smart Gorilla. I am still installing it so I cannot offer a personal experience on how well it performs. Malcolm’s discussion of the “smarts” of the VFD controller is exactly what I would guess about the way it works. I designed controls for nuclear reactors in my working life. While Oneida does not cite Bill Pentz or put his name on their Gorilla, they have clearly been reading his well-posed arguments for more CFM to reduce fine particulate. Pentz recommends 800 CFM for most tools. This is clearly justified if you monitor particulate levels in your shop and know what level makes you cough. The problem is that the tools themselves have 4 inch ports which is really hard to get 800 CFM through using a conventional synchronous 3450 RPM motor and impeller. Pentz’s recommendation is increasing main duct size to 8” and increasing port size to 6” which varies between hard and impossible to do depending on the tool and is always ugly. The alternative which Oneida pursued is increasing RPM with a VFD. This works by increasing pressure across duct so that it delivers 900 CFM through 4” ports. It turns out to be cheaper too. The downside is noise. Not so much at the blower and impeller, but turbulence at the tool generates an impressive roar. So instead of upgrading your dust mask, you upgrade your hearing protection. I came down on the Oneida side of the trade-off. The machines were already loud.