Disclaimer: My comments are about urban areas where smoking is more contentious and smokers are expected to avoid exposing others to their smoke. I realize that different areas will have different attitudes toward smoking, and smokers may be more brazen. In those areas, what I'm saying may be less relevant and it may be more worth vaping in public. I can't really speak to vaping in those places, and I assume that those different attitudes play some small part in the differences of opinion here.
IMO it's important that we be good citizens for the time being. There is no logical reason for the bans that some cities have enacted, but they are happening because, at least for the time being, it doesn't appear much different than smoking to most people, and to non-smokers it's still pretty rational to want to avoid exposure when the risks are yet unknown. I've generally found people to be a lot more accepting once they realize that I'm vaping and not smoking, but I think that it's important to keep it that way. The more that we self-regulate now, the less backlash there will be in the short term and the more freedom we'll have in the future when more people know about vaping and recognize the difference.
Right now it seems like we're hitting critical mass, in which more people know about it and it's becoming more common to see at least one vaper in a group of smokers. If we take care to vape where smoking is accepted (or tolerated, at least), then people will be exposed to it in a context in which they're prepared to be, and will be pleased to find that it doesn't affect them the same way. OTOH, if we're vaping where smoking is unthinkable, then people are going to have that initial shock of thinking that it's smoke and, rational or not, their subsequent thoughts will be all about justifying that initial reaction. I think we also have to keep in mind that just because people aren't reacting visibly doesn't mean that they're entirely accepting; a lot of people won't confront you no matter how much they may dislike it. Instead, they'll just go home and talk about how it should be banned.
I do think that we should be afforded a little leeway to vape in a few places where smoking is not allowed. I don't think there should be a problem in an out-of-the-way corner or a place like a bar, as long as the owners/staff give permission, and I don't see a problem with vaping in most outdoor spaces as long as we make a small effort not to envelop people in clouds of vapor (especially kids). One of the nice things about vaping is that it doesn't smoulder, so waiting an extra 5 seconds for someone to walk past will avoid exposing them to really any vapor at all.
Lastly, if we don't show some restraint, then people will think it less credible when we talk about vaping being harmless. People are funny about others' addictions, and when they perceive someone as being so addicted that they can't control themselves, and can't wait 10 minutes for their next fix, then it doesn't matter how much science you have to back you up; they'll see it as inherently bad and make blanket assumptions.
The bottom line is that the more courteous we are now, the more leeway we'll get in the future until, hopefully, it's accepted as harmless and the general population can see a cloud of vapor and not assume that it's smoke. Until then, however, pushing a "deal with it" kind of attitude is more likely to result in backlash, and make us look like fiends that are so addicted to nicotine that we have to be regulated because we're incapable of regulating ourselves.