eh, it's a analog signal it'll be servicable. just make sure you either buy top of the line 50m cables, or get yourself a repeater at higher resolutions.
I'd say the crappy type that come with a monitor will work to say 6memter or so but beyond that at 1280x720(or 13xx by 766 or something), i'd get high quality, extremely well shielded cables. Coaxial type arent needed yet, but above 20meters, you should think about it.