There are some very well known products such as Herculon, what makes your product better/worse then it? For epoxies, there is only 4 manufactures of the epoxy polymer, and everyone take the epoxy and adds their own additives, is this the same for your coating?
I did a lot of research into this topic when I had my hot water tank go "****" actually it went more of a gently mist....
But it was also at the time I needed to add the hot water for my garage in-floor heating, so I did a huge study on it. Especially the instant/tankless solutions.
My 2...
Its sad but generally you get what you pay for. Your garage is not the most friendly of environments... but it can be an amazing room to live in. Just remember most people won't blink at $5 /sq-ft for hardwood in a kitchen (plus install). Doesn't your garage deserve the same treatment?