This question may come off as a bit off topic : people often say cryonics is a scam. Which is the evidence for that, and to the contrary? How should I gather it?

The thing is, cryonics is a priori awfully suspect. It appeal to one of our deepest motive (not dying), is very expensive, has unusual payment plans, and is just plain weird. So the prior of it being a scam designed to rip us off is quite high. On the other hand, reading about it here, I acquired a very strong intuition that it is not a scam, or at least that Alcor and CI are serious. The problem is, I don't have solid evidence I can tell others about.

Now, I doubt the scam argument is the main reason why people don't buy it. But I'd like to get that argument out of the way.