Thanks for the response. I'm presently in Europe without steady internet access but look forward to writing back. My thoughts on these matters are rather detailed/intricate.

For now I'll just say that I think that because people have such strong irrational biases against cryonics, advocacy of cryonics may (unfairly!) lower the credibility of the rationalist movement among people who it would be good to draw in to the rationalist movement. I think (but am not sure) that this factor makes cryonics advocacy substantially less fruitful than it may appear.