I'm thinking on similar lines. Took a look at one recently.
I look forward to reading further advice on this thread.
What do the monthly charges cover?
What is the insurance excess? Will there be any premiums relative to experience.
Do the shareholders have a "say" in new members in the syndicate.
What happens if you all/some of you wish to change the aircraft?
What will happen to Drawback? To the individual or go in to group funds.
Engine TBO
Web based booking system?
Where is the maintenance being done?
Will it be up to the user to clean the aircraft?
What will happen who will decide on new installations (GPS etc.)
I look forward to hearing all the "iffy" elements of syndicates!