I have a lot of time for both Sam Harris and Dan Dennett. I find I often disagree with Harris, but his arguments are usually interesting and well-considered. The disagreements I have with him are often subtle, as in the case of The Moral Landscape, where I think his moral framework is perfectly valid and useful but not the only objectively correct one.
I seem to agree with Dan Dennett most of the time. I like his thinking on consciousness, religion etc, and I admire his gentle, humorous and thoughtful way of expressing himself.
However, Harris and Dennett find themselves in disagreement on the subject of free will, and I have to side with Harris on this one. I think the disagreement is an important one when considering questions of moral responsibility.