there is no CIS for the mk2 which means your ink costs will be very high. either teh R2880 or the R3000 are very good printers.
I agree, this is another consideration but do most users actually benefit from a Continuous Ink System? I know you have to factor in the cost of the system itself and ink savings of around 60-80% can be achieved but you need to be producing lot of prints!
I've heard good, and bad reports regarding CIS from fellow P.S. members.