I can definitely second this review! Problem after problem with each and every update while old bugs still remain (html code showing up in iPhone calendar event Notes).
When my site was taken down, I read through my php error log and found the following error [slightly edited for security reasons]:
[31-Jul-2013 01:32:53 UTC] PHP Fatal error: Uncaught exception 'Ai1ec_Database_Error' with message 'Unknown column "force_regenerate" is present in table "[redacted]_ai1ec_events"' in [redacted]../plugins/all-in-one-e
vent-calendar/app/model/class-ai1ec-database.php:380
I logged into phpMyAdmin, found the ‘force_regenerate’ column and deleted it. Then my site came back online. I installed the calendar themes and now everything is back up and running (no constant update reminders, etc).
I hope this will help someone in the future.
