Well, when I see someone using a bandsaw, they're usually running a piece of wood through it with their hands near the blade. Cuts seem relatively likely, severity seems moderate.
With a waterjet like the one I use, you would generally have a computer moving the nozzle and not even have a reason to be near the nozzle. It also sounds like a jet taking off. I seem to remember the water speed being something like mach 3 exiting the nozzle, but don't trust my math on that. Cutting is done under water most of the time, which muffles most of the sound and splashback.
On the other hand, I carry a card that tells medical professionals how to treat me if I arrive with a waterjet injury. Waterjets don't work great on laminated materials, because when they hit a transition between materials, they tend to send their energy horizontally. This is also true if it goes through skin and hits bone. It basically shoots you up with water, air, and abrasive, which travels along or in your bones. I've never even come close to injuring myself with the nozzle, but it would absolutely be more scary than a bandsaw.
The closest I've come to injury was one day when I felt an eerie sensation of wind on my skin. I grabbed a piece of paper and tracked it down to a 1/4" stainless water line. I backed away and ten seconds later it was a white cone of fog from a leak that was visible for about 15 feet without even feeling wet. The moral of the story is don't feel around for leaks.