Digital BW, The Print

I have an Epson 4000Pro with UT7 and think of switching back to colour.
My only choice beside Epson Inks is Mispro.
I would like to know if there is a real improvment with K3.
In this case I would have to sell it and get a new printer such as the 
new 3800 or even another brand.

Anybody had the chance to compare and tell if it is worth ?

Thanks
Michel