As someone in a similar position, I can only say that Mark (a SFX employee) has answered my and others specific questions about the company, over on TSF, promptly and clearly.
I first considered SFX when entering timesharing about 18 months ago, but found their customer service to be a bit wanting, when establishing a membership with them. I have a much better feeling about working with them at this juncture, and will likely deposit one of our prime weeks in the next few weeks.
You can search this forum using "francisco exchange" as a search term and should find some relevant discussion. "SFX" is too short for the search engine to work with. There was one recently about the new pricing structure, scheduled to roll out September 1.
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Good luck!
Pat