Followup: I gave up trying to do B&W with the 1280. Sometimes I'd get very nice rpints, especially with BO. However, most fo the time I experienced head clogs using the MIS inks on the 1280. It became far too annoying to deal with.
I have used MIS pigment inks on my Epson 2200 with few problems. The summer before last, I was away for three weeks, and I had some bad head clogs when I came home. I tried a few cleaning cycles, then waited a day, and did a few more. I was almost ready to junk the printer, when it finally cleared up. Since then I have very rarely had clogs, and when I do, they are fixed with a couple of cleaning cycles at most. I do try to print something at least once a week to keep the printer happy, but sometimes it goes a couple of weeks. From all I hear, the MIS inks are no worse than the Epson inks in that regard (but you can't use Epson profiles with MIS inks).
As for B&W prints, I have been very happy with the inexpensive Quadtone RIP and its QTRGUI front end.