The trouble with Melody is it can be hard to tell where the FUD ends and the legitimate criticism begins. I would welcome the existence of more impartial/rational sounding critics with inside experience.
I am, as you know, deeply sceptical concerning the prospects of a cryonics technology that works any time in the foreseeable future, for scientific and technological reasons.
The organisational issues are a whole other reason to worry, however. You have a lot of financially shaky organisations (it's an expensive business to run as a charity) run by people who radiate weirdness signals and thus make it less likely for the rest of the world to take their concerns seriously. Which is a failure in instrumental rationality. And Alcor (Mike Darwin in particular)...
I recently found something that may be of concern to some of the readers here.
On her blog, Melody Maxim, former employee of Suspended Animation, provider of "standby services" for Cryonics Institute customers, describes several examples of gross incompetence in providing those services. Specifically, spending large amounts of money on designing and manufacturing novel perfusion equipment when cheaper, more effective devices that could be adapted to serve their purposes already existed, hiring laymen to perform difficult medical procedures who then botched them, and even finding themselves unable to get their equipment loaded onto a plane because it exceeded the weight limit.
An excerpt from one of her posts, "Why I Believe Cryonics Should Be Regulated":