I have no idea what PS is, but I used to use these inks. I thought it was a great idea, and the way forward. It turned out to be possibly the most costly mistake I've ever made in photography.
Now I don't want to knock Marrutts system, its actually pretty good, but not perfect. However the reality is that when it comes to printing all the huge order runs I got, it was slow and needed lots of attention and monitoring.
Worse, I received plenty of customer complaints. Many customers complained that they could see it was a inkjet print and didn't like it.
Since then I get all my prints done at a genuine professional lab*, much better quality images, no complaints, quite the reverse in fact, it takes up much less of my valuable time and its not that much more expensive.
With that experience, Marrutts system is great for general office paperwork, draft prints etc. but I'd never use it for customers prints.
When I need to print onsite and print instantly I use dyesubs.
*please note in my professional opinion most of the cheap 'professional' labs on the internet are crap. Absolutely fine of course for your average snapper, but in no way professional grade prints you should be supplying to your customers.
Although I posted this I don't get ink from Marrutt but I do use one of the inksets it sells....made by an American company. I use it with my R2880 and to date I have been quite impressed. Prints seem identical to those from the days I used Epson inks ..... But at a quarter of the cost. No-one has ever knocked the print quality from the epson R series printers to my knowledge......the inkset is used throughout the pro range and so is the printer head I believe.
I personally wouldn't use something like the R2880 for long runs even with a CIS unit fitted.....but I do know that Marrutt supplies 220ml carts for large format printers and these would make more sense for this type of work.
One benefit of buying either ink or paper from Marrutt is you can get free profiles made to ensure a proper colour response.....custom made printer profiles are worth having and can dramatically improve print quality.