I skimmed the comments on this article, and it seems like the prevailing attitude is, "if you're not signed up for cryonics, then you must either be irrational, or you must lack a desire to prolong your life (which means you're irrational anyway)". But I think that's a false dilemma. There's at least one other option: "you are rational, and you want to prolong your life as much as possible, but you're not convinced that cryonics can actually accomplish this". I personally fit into the latter category.
Do we currently have any evidence that it's actually possible to revive a mammal after it had been cryonically preserved, with (and this is the key part) its memory intact ? Or is it the fact that, once your brain activity ceases, your personality is gone -- in which case, even a transhuman Singularity-grade AI won't be able to bring you back ? As I said, I'd very much like to live as long as possible (ideally, forever), but that doesn't mean that I must therefore uncritically accept any proposal that promises to accomplish this.
There are people whose brain activity has ceased, who survived and still consider themselves to be the same person.
If you think living forever is worth money, it's reasonable to sign up for cryonics even if it's unlikely to work, because the other options (being buried in a wooden box or burned to ashes) are considerably less likely to work.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: