I sugest Black Goat. Several times at my play group we hand BG to the newbie and hr/she wins. As the more experienced tend to avoid attack the newcomer BG goes very well if ignored.
That's exactly the opposite of my experience. I find new players have the most trouble with Black Goat.
My recommendation for first-timers, in order of ease of understanding the faction and how to play it:
2. Crawling Chaos
3. Yellow Sign
4. Black Goat