from my experience: don't buy a brand, buy the best service you can get. the closer is even better.
signage printers are more robust than fine art printers, and much more expensive. they are workhorses but eventually at some point you are about to have to service the printer. and here comes the time and money consuming part. if you will have a very good technician to help you will lose less time and less money.
regarding gamut: signage is not as demanding as fine art. you are looking at the prints from meters away so it doesn't care so much if you print 1400 dpi or 720 or even 320 for a very large banner far away. from my point of view 4 colors or 6 color are about the same regarding signage gamut, but with 4 colors you have less ink consumed and less profiling problems.
as far as latex vs ecosolvent after a long google on the net I give up buying a latex due to the fact that I find them much more sensitive to the environment variables and dust. but this is my shop, maybe it is not you case. also it is a bit harder to get the right settings for different materials, especially the heat sensitive ones.
PS not a recommendation and not advertising anything, but I have a Roland for 7 years and it is nothing comparing to my Epson. Much more industry grade build, a lot less complicated and much more robust. the simpler it is the less prone to get broken.
my 2 cents.
