I could be wrong but my online research seemed to indicate that the hyper engineering product was actually the first generation unit designed by Matteo Giovanetti, also resold by dometic under the smart start brand name. There is at least one video online of Matteo demonstrating the hyper engineering product at a trade show.
I believe that a few years ago Matteo left hyper engineering and started working for micro air and has since designed a newer, improved soft start device.
As an example the micro air easy start has a built in 5 second delay between fan start and compressor start - allowing a generator to first spool up out of eco mode to start the fan before going full throttle to start the compressor. This saves fuel because you can run the generator in eco mode and it won't stall under instant load if compressor and fan try to start at the same time. Also, the easy start has an IP65 enclosure for water resistance and has a 2 year warranty vs one year for the hyper engineering product.
I looked at both devices (actually all 3 if you include the dometic version which is oem hyper engineering)
I decided to by the micro air easy start because it was easier to wire, had better documentation including videos, had an option to buy all the connectors you need for an additional $10 and better overall product support. Matteo will even supply you with a custom wiring diagram for your particular AC unit if needed / desired.
Matteo is very good about supporting micro air customers, and the airstream community. He is extremely knowledgeable and responsive based on my personal experience.
So I think it is safe to say you get what you pay for