I'm new to Android (former Crackberry user). When I try to "write" an email or text with Google Now voice - text, it cuts me off if I take a breath. If I speak quickly, there is no punctuation...just a long, run-on sentence.
That's odd, it works fairly well for me. Don't have to rush that much, EXCEPT if I'm using Android Wear to do the dictation; then it does cut off a lot quicker than the phone/tablet app.