Not a feud - just very different approaches.
Technically, Sam, Dan, and Richard are allies.
But they have there differences.
Richard really is "fire and brimstone," Sam wants to be the rational spiritualist, and Dan....well in my opinion Dan kind of carries the two by building an expalantory philosophy.
You may also notice that not all Atheists like all 3 of them (well, at least the ones who declare themselves to be individualists).
I've known a lot of people who think Sam is "on crack" and Dan isn't "out there" enough. I know a lot of atheists who while they agree with Rich, think he's set back Atheist PR for another 100 years and would prefer the less fiery responses of Dan. They also tend to find Rich, as a person not as a thinker, to be a bit of a blowhard.
Finally, i know folks who are very enthusiastic about Sam thinking that Dan and Rich don't have an "follow through." In other words, "Ok great..we've proved God doesn't exist..now what?" They approve of Sam's rational spirituality as a means of replacing the emotional void left by the end of religion - a void that they accuse Rich of ignoring and Dan not addressing. (Personally i think they both did address it, just not to the satisfactory conclusion of the respondents).
Wheh.....yeah that's a bit long.