Am I over simplifying this but doesn't the X-Jet and the DS Injector do the same thing? Both use a venturi effect to draw in a solution, mix it, and then apply it? To me the only difference is where you put the injector and some marketing to sell it. I get the X-jet can be tuned but so can a DSI. I understand with the X-Jet you can go back and forth from application to rinse without having to go back to the truck / trailer but in some cases the time I lose lugging the bucket with the X-Jet or if I need to refill it dwarfs a trip to my truck. And before anyone comments I actually use both methods X-Jet and DSI depending on the job I'm doing. Both methods work, both have benefits and drawbacks.
Now what I rely like is my proportioner system, allows me to adjust mixes on the fly. No batch mixing and wishing it was weaker or stronger.