We had a front drive unit fail on our second day of ownership back in December 2015. Got the alert, said power would be diminished, but we were only doing 25mph. We pulled over, called Tesla, did a reboot, everything was fine. Service called the next day and said it was a fault in the front drive unit and it needed to be replaced. They figured this out from the logs. Said we could keep driving it and to let them know if it happened again.
It never happened again.
Two months later, we got a new drive unit and a free alignment. Still no problems.
They are a new company going through growing pains, but certainly make things right if you give them opportunity to do so.