If you have any volume at all, the Gandinnovations machine is the way to go. I'm not sure about the Mimaki as far as machine durability, but if you are going to print all day, you're gonna use a ton of those silly cartridges. Mike's right, the Gandi machines are the real deal, real industrial manufacturing machines. He and I both started with the colorspan flatbeds, so we do know the difference between and entry to mid level machine and a true production machine.
In the interest of due diligence, those Mimaki "map" test prints that you have likely been shown are quite impressive. But, my gandi can do those all day long, though, at a lot faster speed. And, to be realistic, run circles around the mimaki on the vast majority of the work we produce. If you're gonna spend $150k what's another $50k to do it correctly?
I'm not bashing the mimaki at all, it is a good machine for the right fit shop.
The bigger question you need to ask is where do you want to go and what do yo want to spend. The machines you are considering all do basically the same thing, and produce basically the same quality output but at different entry points and operational/consumable costs.
You may want to contact Adam at ASI in Pennsuaken NJ (asitv.com)
They do have the Mimaki in question
