Rip prefers the clean, because it's heavier and because the snatch is harder (more skill). However, some people who can't clean (flexibility, anthropometry) can snatch, so they have that option. The advice seems to be, try the clean first. If you can't do it, try the snatch.
There's also a place for snatching alongside the clean later on an HLM if you want to pull two olympic lift varients on light and medium day.