Don't care what brand you buy, but if you can afford color - go for it.
I purchased a Vista a short while ago when I started caching. My eyes, not being what they once were, have a lot of trouble reading the greyscale screen, particularly in the shade and subdued lighting; and especialy through the clear plastic cover of the carrying case.
As soon as I can afford it, I am going to upgrade to a color Garmin Map 60CS. I have had very good results with the Vista, I just have trouble reading the screen under certain circumstances.
John