I vape all the time too. You don't get that natural pause like you do at the end of a cigarette. My brother, at first, tried to work out how many inhales per cig and emulate that with the ecig, but stopped trying pretty soon. Vaping is a slower way to ingest nicotine, I think - pretty sure I've read that somewhere in all the literature - so you use it slightly differently.
I wasn't worried about vaping in front of people, but people in my small town tend to think I'm a bit eccentric strange, so what difference did it make to add yet another oddity to my arsenal 
Having said that, if I were at a school event - even if it were outdoors - I wouldn't vape in front of the schoolkids (though I might find the bike sheds and vape behind them; somehow, you'd have to do it, wouldn't you?).
What I do do when people are at my house is show them the equipment, before I actually vape in front of them. I think in my early days I made it look like more of a demonstration - look, isn't it interesting? - rather than "I need a fag but I'm doing this instead".
Quite a lot of my friends smoke, and most of them want to give up, not least to save money, so a lot of people around me are interested. 3 or 4 people already have ecigs as a result of evangelising, and another 3 or 4 are getting them for Xmas.
All that said, I still don't see a lot of people vaping, even when I'm in our nearest city. Today I saw 2 which makes it 3 altogether over a couple of months. I tend to do it rather ostentatiously when I'm in the city, I think because I want all those people standing about outside having a swift fag to know there's an alternative.