Hope this is a timely enugh reply...
Most visitors find that Diving Pensacola contains 3 things - Jelly Fish, Stong Currents (near the bay entrance), and High Silt Content (mostly within the Bay).
There are a multitude of shipwrecks and man-made obstr.'s that are all fairly close to shore (within 10 nautical miles or so); including tanks, automobiles, and a few WWII era aircraft.
If you should decide to dive near the bay entrance; be aware that during peak tidal changes strong currents create a virtual vortex of what I like to call sea-slush - a mixture of fine seaweed particles mixed with a dsh of jellyfish that creates a fine haze throughout the water so be sure to wear at least a full glideskin wetsuit w/hood.
Depending on your depth prefferences: I would recommend the USS Mass. (17ft.) for shallow water; The Three Barges or the Liberty Shipwreck(48ft. to 75ft. rsp.) for midian depth, or
Five Army Tanks (at 105ft.) for for the deeper inclinded.
My personal thoughts as a rescue diver and law enforcement officer are that, generally, the deeper you go - the shorter the dive and the greater the risk.
In my experience, When properlly equiped, Pensacola's waters have allways been enjoyable and rewarding. I hope that during your visit you find it same.
As an interesting side note : History has recorded that there are over 220
shipwrecks containing an est. $110,000,000.00 in various cargo within the Pensacola area.
Good Luck On Your Dive.
Happy 4th of July
Have Fun and Dive Safe!