Hi - we have a Riso ComColor - have had it in the shop for just about 3 yrs and previously had an HC (the previous version of Riso's inkjet) for about 3 yrs . We have put over 3 million impressions on these and have tracked our ink costs. We are a small ($450,000/yr.) digital print for pay and copy centre in a community of about 12,000 souls. Our ink cost per impression has average $0.015 per letter sized document in that period. The Riso's have required very little in service (ComColor is way better than the HC was) mostly to do with feed rollers being adjusted, cleaned or replaced. Very useful machine and has been profitable from the get go. It does not replace anything - we also run Ricoh toner machines - but is a great option for many jobs. Envelopes, NCR (numbered in the software), instruction manuals and directories are all some of the applications we run regularly. We look at ink coverage to determine if the job qualifies to be run on the ComColor or should move to our toner machine - high coverage goes to the toner machine (cost on it is about double the ComColor). Of course the finish of the job comes into play as well as does what stocks we need to utilize. As stated - they have their own print head technology and the inks are soya based - they do not need drying time and they are not water soluble. You cannot print on any stocks with a gloss or semi gloss type finish - we find that a good 24lb. stock will work well - of course the better quality stock the better the look of the finished product. I am more than willing to share our experience on these machines also on the Riso duplicators which we have been utilizing instead of a small press for over 20 yrs. Many applications that are profitable, easy to train operators, very low service requirements and cost, small footprint and extremely low power requirements (no fusers to run) - all make this an attractive addition to any print operation. And no - I do not work for Riso!!