I picked CI, and have stuck with it, partly due to the cost, and partly because its board is elected by the membership; while Alcor's board selects its own successors, which seems to me to be much less democratic and to be more likely to have something go terribly wrong organizationally before revival becomes possible. (You may have different theories about long-term organizational survival, but given the scarcity of evidence to work with, it's all-too-easy to rapidly run into 'politics is the mind-killer' level arguments.)
Skimming the top of the thread at https://www.lesswrong.com/posts/PdcpEih96tqrt2waM/alcor-vs-cryonics-institute , one relevant thing I've learned is that Mike Darwin is both heavily involved in and quite experienced with the cryo community, and always seems to be willing to tell everyone what they're doing wrong. This approach has caused some social friction, and as far as I know, he spends his time these days in the cryonics subreddit instead of the mailing lists.
You might want to join the New Cryonet mailing list at https://groups.yahoo.com/neo/groups/New_Cryonet/info , which has members of both Alcor and CI.