Thanks for the input from everyone! I have more info that may prove useful...
I just had a 3rd party insurance broker evaluate both Proper and CBIZ in North FL.
The Proper policy was better overall, but the wind premium was very high.
The CBIZ policy had a more reasonable wind premium, partially because they allow a 3% deductible rather than insisting upon using the same deductible for all coverages like Proper does. My lender required a $1,000 deductible, so this made Proper very expensive. The Proper rep in North FL seemed to think I could get a "wind only" policy anywhere... which is wrong. Insurance brokers will only write "wind only" policies through the state-run "Citizen's" and only then as a last resort.
The main weakness of the CBIZ policy was very poor O&L coverage. O&L stands for "Ordinance & Law" and essentially it means "If there is an ordinance that says you have to demolish your property entirely and rebuild it completely, to code, if it's more than (say) 50% damaged... the additional coverage for that is X". The Proper policy had "full coverage" and the CBIZ policy had almost none.
The coverage offered depends on the property itself. CBIZ didn't offer O&L coverage to me because my property is very old. Older properties are generally more expensive to rebuild to code from scratch.
The limited amount of information available suggested to me that the neighborhood's historical preservation guidelines would prohibit demolition if at all avoidable, so I've kept my CBIZ policy... and I'm hoping to avoid any surprises should the unthinkable happen.