I used to work as a design engineer for an AWJ cutting facility, and I've seen plenty of the big machines in action. I'm more than skeptical here.
Read the reviews...there's more than a fair amount of concern...and for good reason.
Waterjet machines basically "eat" themselves to death. And by this very nature, there are very high maintenance costs for just about every component of the machine. That's why industrial AWJ hourly rates run in excess of $100 an hour. This isn't addressed in their video.
Also...who supplies aftermarket parts in the event the company closes its doors?
Water pre-treatment is crucial for long pump life on industrial models. Nowhere did I see anything mentioned about that.
A few other details (slow cut time, excessive garnet usage, etc...) will not make it very economical when compared to using an industrial source to do your cutting. Spent water disposal is not so tidy...it needs to be filtered through a weir system before allowing it to return through your home's pipes or you'll be helping a plumber make his mortgage payments.
Not being a "bubble buster", but I see it more as a time and material consumer than being a useful tool.
Make your money doing what you do best, and hire an AWJ source to do your work.