Had 2 Boxxer 421s... air cooled little guys that packed a big punch. Both were used, both came from sources that didn't care for them properly. Not a machine that I'd trust to carry a company past 4,000/5,000 hours personally, but that's more of an air cooled vs liquid cooled engine thing. They get plenty hot, and will handle a 200ft run with minimal drying issues. Two jetter wand for sure, imo.
Upgraded to the Titan 575. First one was flawless. Heat was remarkable, suction was awesome after running Boxxers for awhile. They do like to vibrate, and checking / tightening bolts often is a good idea. We had a problem with the diverter arm up front disconnecting, which would cause the machine to keep heating... it's a bad deal when it happens, unless you're into burning the crap out of yourself trying to get back up in the middle of a job.
When it was time to add another van to the fleet, bought another 575... and it was the biggest lemon I've ever encountered. Right out of the box it gave us nothing but problems. We got to test the whole truckmount guarantee, 30 days blah blah blah… it didn't go like that. Ended up taking it to service 6 times I believe, and two different locations. Nobody could figure it out, but nobody was willing to swap it out and let us get on with busy season either... all while still making the payment, might I add. It escalated, and I actually had to contact Hydramaster directly over it. By the end of it, the Titan was pulled out of the van, and a CDS was put in it's place.
After running the Titan (that ran), I wasn't real big on the CDS, but I can see the appeal... especially with employees/technicians out running them. Very minimal problems, very minimal maintenance comparatively. We ended up selling the original Titan and van (that ran), and replacing it with a new van running another CDS shortly before my departure from that company. At the time, the first CDS was having some serious overheating and electrical issues, but I left before learning what the deal was.
I'm back on a Prochem now, and happy about it. All in all, I love all 3 machines for what they are, and if I had to choose one it would be the 575, despite the lemon incident.