Left 270, extremely clear as you'd expect. I actually got so caught up in my first flight with it in on that I didn't realise it hadn't turned on by itself and wasn't till part way through the flight when I was trying to figure out why calls were difficult to understand that I realised! After that no problems.
Of course if you're an Apple person then you can also use the Flight Link App which records all comms and allows you to play them back as well!