Had a truevis, now I have a cjv150, the machine work perfectly, it doesn't go through a cleaning cycle every time you boot up, instead it 'refreshes' hourly, consuming one drop of ink every now and then. (overall ink waste is the same as truevis's). Ink is cheaper, the machine produces fantastic colors, very happy with it. On the other hand mimakis Rasterlink is garbage compared to Versaworks. It's not that you cannot use it - you can, but it's ugly and slow and freezes some times and so on, you cannot RIP if the machine is turned off.
Compared to CMYK : orange has effect only on skin tones, so you need it only if you print portraits, on the other hand Lc Lm (not Lk) make s a huge difference when you print grays or gray gradients. Don't even think of silver or white unless you know exactly why do you need them.