Looking for alternatives to Epson Ultrachrome pigment inks

I know there are lower-cost/bulk alternatives to Epson Ultrachrome inks, has anyone here ever tried any?

In addition to Ultrachrome I've used Pantone ColorVANTAGE carts (old stock from eBay, occasionally available), colours are in line with genuine Epson offerings and the carts are recognised as genuine by the printer. I only see these occasionally though so want to broaden my search.

Obviously I want a good quality ink that's not going to clog and colour reproduction is important - I'm able to profile papers/inks but I don't want to do this any more than I need to. I've seen various suppliers offering bulk ink with refillable tanks and options for CISS but I'd sooner go by other peoples' experiences rather than take the manufacturer advertising at face value.

One other thing, I don't want dye-based inks as I need the longevity of pigment inks.

All input most welcome!