I got one of the 1st Ricoh Gelsprinters models for testing a few years back, even before those were setup for sublimation. The Gel pigment inks worked just like OEM Epson pigment inks do.
The washabilty (using good papers) was very good, just like Epson. Also, just like Epsons inks the graphics had a slight shift to yellow when heat transfered. Ricohs OEM inks I calculated to be about half the price of EPson OEM inks.
3rd party inks in Epsons are much less cost than the Ricoh OEM inks are though, and you can get a 13 x 19 Epson WF1100 for a fraction of what a GX7000 Ricoh costs and use Cobra inks very cheaply and they don't color shift when heat pressed.