Annette is right--multiple offers have been rare in the past couple of years, but according to the FAR (Florida Association of Realtors), we have hit bottom and this trend will continue(!), especially on well-priced properties--the trend has already begun with foreclosures and short sales.
The best offer, as Louise pointed out, is going to be the one MOST LIKELY to close--which means all the pieces must be in place--price, time frame, and some "skin in the game". Most if not all lenders are now requiring a mimimum investment by the buyer of 3.5% (FHA down payment), even when the buyer is also receiving down-payment assistance. Since Pinellas County offers $10K or more to buyers who qualify, if any offers are from CDC assisted buyers, it's still a good idea to speak with their lender and make sure they've got some cash reserves at least--the days of zero-down are gone, perhaps for good!
Of course, a full-priced cash offer is always going to be the best! Good luck!!