Florida is not an open carry state so I do not have the choice regardless of my intentions.
Given the last 4 pages I have read, this is probably not the time or place for proposing we engage in a rational discussion of what I consider a complex issue - more complex than the emotional debates usually reflect. But what the hell!
Clearly, in some instances, open carry will be a deterrent. Most less-than-dedicated criminals are going to opt for easier targets and so, seeing a handgun on someone's belt (even seeing someone whose demeanor clearly says "don't **** with me"), will be likely to move along.
But it does seem that not all modern criminals are less-than-dedicated and their crimes are not always simply the "of opportunity" variety, so they may not be deterred (e.g., 4 armed robbers may not burst into a pawn shop, see an open carrier and run back out - there was the recent armed robbery of a gun store in Kansas [?]). At that point, open carry may confer some advantage with regard to preparation and ease of access.
In addition, when the assailant is either a sophisticated criminal or, as in Paris and other instances, a fairly well-trained and committed criminal/murderer who is fearing failure more than death, I suspect this gets more complicated. That is, while we are all trained or training in skills like situational awareness, scanning, identifying priority threats, can we assume criminals and jihadists are not? If we are all working at being aware of baselines in our environment (what is normal and expected, what we want to see and what we do not want to see) and looking for anomalies and deviations that indicate likely threats and suggest their priority, can we assume our antagonists are not also thinking in these terms? Can we assume they are all in condition white while we are in yellow?
So - I'm watching those around me, looking for people who stand out in the environment, whose behavior is not the norm for the context, who may be threats. They way they look, the way they act, how well they are focused on their own activity v. others, even whether they are armed. Do I assume an armed person is a threat? No. Does it mean they are more of a threat than others may be? Yes. In essence, I am trying to get and stay "left of the bang" (a great read, btw). If the criminal - more especially the jihadist - is also doing this, using these skills (why wouldn't they), then is the weapon on my hip an anomaly (not what they expect, not what they want to see) to be dealt with immediately as a threat to his plans? If they do not have the option or interest in moving on due to target value or sheer fanaticism, then does open carry create a priority target for them? Or, perhaps, they are just going to immediately kill everyone so it does not matter.
Before everyone on whatever side of this issue gets all red faced and pulls out the long list of derogatory names and comments we usually see - have seen in this thread - I am not advocating or criticizing people's choice to carry as they want - this is not a choice I can make in my state and thus my options are clear for now. I, truthfully, have no investment in which decision someone makes and am glad they can and do carry, however they decide to do it. Clearly this is an emotional issue in our community and, as usual, everyone runs to their favorite side and assumes everyone on the other is an idiot. I prefer not to align myself with fools of any persuasion, so I will not do that because, as noted, evidence for or against is largely anecdotal and impressionistic. There is no valid evidence in either direction (news reports and armed citizen incidents are not valid scientific evidence).
I merely think that, in the absence of good outcome data on the different approaches (not that we will ever really have it) it is good to ponder the question conceptually, not emotionally, and see both its potential pluses and minuses.
So - my piece is said - flame away if that is all one needs to do. The whole macho BS of who has and has not is sad. I take such things too seriously for that; I prefer to train people to think through such issues and make decisions that work for them.