Initially they will look nearly identical. Look a few years later and one will probably have scratches and the other will not.
I'm going to go on a limb and say that most people that frequent the boards here aren't going to have the same Apple Watch even after one year if a newer model is released to see how the screen holds up against scratches that far down the road.
AC Plus seems like a steal for the price and a $69 service fee to replace a Sport, which I am getting.