I am currently signed up for neuropreservation through Alcor, funded by an indexed universal life insurance policy.
Why
My primary motivation for cryonics is preserving optionality. I find it pretty plausible that the equilibrium of philosophical reflection will conclude what is valuable is consciousness-moments, rather than people. It might turn out that there isn't a meaningful difference between there being experience moments that have continuity of identity with "me", and there being equally meaningful experience-moments that don't, in which case cryonics doesn't buy me anything.
However, I absolutely do not want to make irreversable decisions (like allowing myself to die irretrivably), on the basis of my current, non-equibibrium, philosophical intuitions, generated by my monkey brain, in an infant society. I want to punt questions to the future where (if things go well) I, and society, will be much smarter and much better informed, and can have much more confidence in our philosophy. Cryonics is the action that preserves options for my future self, while regular death doesn't.
Additionally, signing up for cryonics is a costly shibboleth of being part of a tribe that is defiantly opposed to death, and I like that aesthetic.
Will it work?
I haven't looked into the technology in that much detail, but it seems like a pretty good bet that cyronics can work: that there's a greater than 30% chance that cryopreservation preserves what's important about a person's soul such that the technology of the future can bring them back.
However, my best guess is that cryonics will not actually pay off, because humanity will go extinct before revival is possible. Whether or not human civilization survives seems to me to be most of the crux of eventual revival. (I decline to give a specific probability estimate of extinction.)
Neuro vs whole body
It seems pretty likely that important soul-relevant information is stored in parts of the body other than the brain, in neural tissue or in other body systems. However, the clear majority of soul-relevant info is encoded in the brain, in particular, and whole body cryopreservation trades off somewhat, against the quality of preservation of the brain.
My prefered cryopreservation method would be to sever and preserve the head, and then also preserve the body, separately. As far as I know, no cryonics organization currently offers this, but I might look into trying to set that up as a custom arrangement with Alcor, when I'm older and richer.
Charity
When I was younger, I had a rule that for every dollar I spent for myself (which in practice mostly meant purchasing personal development materials), I would donate an equal amount to charity. I dropped this policy when I discovered x-risk, deciding that I should be much more unreserved about investing in my own capabilities. Cryonics is the only major (>$1000 a year) purchase that is clearly just for me: my being cryopreserved does not significantly improve the world or increase my own capability to improve the world.
So, I decided to apply my old policy to my spending on cryonics. I now donate $