I would suggest the Roland. The metallic ink gives you entrance into a whole new developing market (even if the print speed with metallics is dead slow). Also Roland seems to have an edge on Epson in the signmaking market.
I've made some research recently and saw some demo of both machine.
-Epson have, by far, a better print quality than the vs-640.
-The ink droplet in epson is around half the size of the roland.
-The ink of the epson is cheaper. Even with the 8 colours.
-epson use 990ml cartridge and roland 440ml.
-newer printhead on the epson. (roland use epson printhead)
-The epson have a take-up real, the roland is sold separately.
-with my areage of sqft per month, if I don't use the white and silver, the roland will cost me around 70$ in white and silver into waste.
-the silver ink cost around 1$ per sqft
-I like the idea of a separate cutter.
-with Roland, on glossy vinyl, the silver ink fade out when you pass your finger on it. So you have to laminate everything.
the price I can have here for roland vs-640 + take-up and epson gs6000 + graphtec FC-8000-160= epson is 2k over roland.
I did'nt make my mind yet, but I think you can tell me where I go...