I too have been working with the 11880 for a couple of months. I've been meaning to write a brief hands-on review, but somehow time has gotten away from me.
All I can say is that if you need a 60" production printer and have a spare $15,000, this is the printer to buy.
This technology, heads and ink, will show up in a new line of Epson printers next fall. In the meantime, it's in a class of its own.
Michael
UPDATE
Just to avoid any inappropriate assumptions I'd like to clarify that the sentence above about new printers from Epson in the fall of '08 is simply educated speculation on my part. Clearly, the head technology that's in the 11880 will likely migrate down to less expensive models. Why wouldn't it?
Also, 2008 is a Photokina year, and so new printers from Epson as well as other printer makers are more likely to appear then than at other times, especially since Epson just updated their Pro printer line a few months ago.