Riding against traffic is too scary for me. But riding with your back to traffic is scary, too, because you never know when a motorist is distracted by texting and the auto swerves into you.
Either way, there will be risks to factor in; however the game of baseball may serve as an analogy:
The batter while facing the pitcher is able to see the approaching ball and can react in most instances and duck away from the pitch; but when the player is running from first base or any other base, the runner can not see a ball coming towards his body or head, frequently the runner can be hit be the thrown ball.
My conclusion is that facing traffic is a better situation. Your eyes are an addition to the eyes of the motorist thus the meeting has the benefit of dual vision.
I was thought to always face traffic as a pedestrian and in this case a cyclist. In fact, motorist must yield the right away to a pedestrian or a cyclist. Motorist should always be in control of their vehicles.