Gender Test at 10 weeks?

I just left an appointment and they told me about the genetic testing that can be done to predict your baby's chances of being born with a particular disease, but she told me about a different test that is 4-in-1 and includes the gender at 10 weeks.
My questions are:
1) Has anyone done this? And what was the end result (as in the correct prediction of the gender)?
2) Was it preferable to finding out via the ultrasound?
3) If you haven't done it, what are your thoughts?