My wife has a small frame - rides amazingly well and it seems planted and balanced. 168cm is on the cusp between S and M .. check your inseam v dropper height. If you have long legs v torso the Med with longer dropper would be better.
I was an an early adopter .. or so I thought. Paid in full through the LBS months ago and the sands have run through the hourglass many times, yet no sign of the unit. 1st world problem from living in NZ?