I don't see what the rush for signing up for cryonics is all about.
My understanding is that while I'm young, accidents are the most common cause of death, and it's hard to cryopreserve someone after an accident & cryonics works much better if you die in a hospital. So being covered for cryonics isn't that useful when you're young.
Once you accept that premise, it seems like you're better off just putting more money in to your retirement fund or other investments in order to pay for your suspension when you're older. Putting money in your retirement fund has tax benefits, and you'll actually make money through the interest you earn rather than losing money to an insurance company. (Insurance companies are only profitable because they take more money in through premiums than they pay out, while the stock market has historically gotten decent returns, at least in the US.) I don't find Rudi Hoffman's reasons to fund your suspension through insurance very convincing.
As an added benefit, you can put off the decision of whether you want to go for plastination or not, whether you're wealthy enough for full-body Alcor as opposed to head-only CI, and maybe other things until you have more information about cryonics technology and how much money you're going to earn over the course of your career. (Another possibility is that the cost of cryonics will drop drastically and you'll end up with way more life insurance than you wanted.)
Even if signing up through insurance is marginally better, it seems like a relatively small optimization, and I feel like I've got much better things to do at this stage of my life.
(FWIW, an LWer friend of mine who is a finance professional with a history of achieving above-market returns did a fairly thorough analysis of this, factoring in the possibility of an early un-suspended death, and independently came to the same conclusion I did.)
Most of the time, when I listen to discussions like this I hear, "How much exactly do you want to not die?" To which my unequivocal response is "A WHOLE FUCKING LOT."
In the past, the Cryonics Institute has had a policy that said that they would not accept anyone who is not a member. This has changed. The policy now is that someone who has full legal authority over your body can sign you up after you die. It costs $36,250 to be frozen if you are not signed up, which is more expensive. They also will not do anything until you have been on dry ice for 2 weeks after they have been contacted, so not being a member is more risky.
This is very important news for anyone who is currently cryocrastinating. It means that you can drastically increase your chances of survival without filling out any forms. All you have to do is tell a loved one you want to be frozen upon death, and that you would like them to take responsibility for making sure this happens. This takes literally 30 seconds. Do it now!
This news might also be a reason to not sign up right away, if you think something better (like radical life extension or uploading) will come along in your lifetime. We should discuss this in the comments.
Edit: The general consensus of this discussion is that this is a really bad reason not to sign up for cryonics.