Well, I don't have a mosquito counter, so I can't confirm or reject the hypothesis in a controlled double-blind prospective study that there are fewer mosquitos with the mister in a timer. But, it's pretty clear there's been a reduction. Not complete 100% probably because! as you mentioned! they can come from all over. But, the "locals" don't seem to enjoy our space in the same way as they had in the past. And, I am quite familiar with the concept of the placebo effect in a research context, and I am quite confident that doesn't quite apply here.
Anyway, the OP was asking what has worked in people's experience, and I'm relating my experience. And, in my experience, it has been an outstanding method for mosquito control. I cannot speak to the possible environmental hazards, as I simply do not have enough information to make a determination one way or another. But, for our backyard and for the problems we faced, it has been quite effective.