I used to make my living here. First of all, over the last several years, we have seen a deterioration with Riso in support, inventory (especially parts) and innovation. Their attempts to reinvent themselves have not been successful. We have jumped ship and do the Ricoh PriPorts now.
As far as the industry category of the Digital Duplicator is concerned, the niche is now so small that it hardly merits mention unless you feel that our industry is going the way of specialty.
The niche now usually involves a specialty application on a media that doesn't do well (if at all) on a laser device. For instance, multiple part forms if you find someone still using those. You might still find the need to run 1-5K envelopes which is too much to try to do on most $10K or cheaper machines and too few to get the price breaks from internet suppliers, especially if they want external messages that change regularly. I'm not talking about variable data. That's a whole different discussion (despite Rico's attempts to do even that with add on accessories).
Obviously, long-run spot color is still way too expensive on a laser device compared to a digital duplicator if you are OK with the quality.