Their update 11 (here until they break the link, sigh) contains a bunch of discussion about the Sep 18 LAFCO meeting that corresponds to my recollection, and goes into details of the financial analysis.
There is a letter from Sharon Burke, extolling voters to explore the issues and make up your own minds, and offers some arguments I haven't seen before:
One of the primary motivators for incorporation is the desire to protect our taxpayer funds from the excessive benefits the County agreed to with its unions. These costs are killing the County; it has no choice except to use County employees and overhead to perform municipal services for Alamo. An incorporated Alamo can contract out these services to private suppliers.
I'd implied that before, but never seen it spelled out clearly. Those who think the County might slide into bankruptcy ought to consider this seriously.
Third, there's passing word the AIA has institutionally voted in favor of the Incorporation, even though it will probably bring the demise of that organization.