Many get confused with all the blurb out there, as Matt says, at the business end all systems are the same, pure water pumped up through a brush, and the rest is up to you.
Someone on here was extolling the virtues of and Ionics system, and how it made him more pro, inferring the system got him more work...quite how I'm not sure as I also read in another post how he keeps the back of his van locked (sensible, not criticising) and has his hose plumbed in through the side of the van.
So no one is going to see his flash system anyway!
And I've yet to find anyone outside of window cleaning circles who has the remotest comprehension of who or what Ionics/Brodex/Omnipole are! Or any of the other top end manufacturers are.
Get what you need, not what you want.
Though if you have deep pockets then go for the big expensive systems...
Ian