Not to thread hijack, but I am in the same boat, we run a 1604 and 1304 here currently, and I'm not sure what my next step is. I've heard good feedback about the latex printers, especially the new 300 series from HP. However, I must say that I really haven't had much to complain about with these Mutohs. The single head DX5 prints great and is easy to maintain and I run 3rd party ink which really helps keep my costs down.
The downside I see on the latex is that you're "stuck" with buying consumables like heads and ink from HP and if they want to all of a sudden want to double the price of those items who could stop them from gouging down the road? I dunno, I guess I will keep running these until I have a solid reason to upgrade...