Did you mean 4:2:0?
Here's a link:
I think normally with video it shouldn't really look that inferior to 4:4:4 most of the time. The differences will be more obvious with CGI/test cards.
But if it doesn't require any increase in bitrate (might it even take less bitrate?) to have the full 4:4:4 colour for compressed video and it will always have the full quality I think it's worth using.
Edited by Joe Bloggs - 8/29/13 at 11:45pm