I listen to my messages the same exact way as I am talking on the phone, unless it's on speaker. But I've a feeling it's the proximity sensor that initiated Siri, so you don't have a choice, but to turn her off. And her getting my commands wrong is probably because my car isn't quiet enough.
But I think google voice is where it's at. It needs a trendy name too like, Stan or something. Then it would kind of work if I said "Stan just raped Siri".
That is a good question. At the time I was testing it out I was probably speaking more into the bottom on the phone than the top. Now that I have a car mount for my phone I suppose I would be speaking more towards the top of the phone (it would be sitting in lansdcape orientation with the top of the phone pointed towards the driver's side).
You mention that you use Siri to read your text messages to you, do you also have Siri compose text messages in response? That is where most of my issues are. The resulting text I get is usually so far off as to not be usable. For placing calls I think Siri works quite well.
That's HILARIOUS. When i use google voice with google navigation in my car, it works perfectly, even with lots of ambient noise with my windows rolled down. And i have a really shitty phone too (motorola triumph).
Google Voice is not the same as Google Now.
BTW Google Now is more accurate and intuitive than Siri at the moment.