I personally uses Esso gas reward points and I find that the points add up really fast. Besides, if you have other credit cards such as RBC Gold card, you can exchange RBC points for Esso points. Then this will allow you to redeem points for car wash regularly. Their touchless car wash system is quite good and always does a good job of keeping my car clean. Though they use to put more thicker soaps foam during the car wash before, I have noticed that they started to use less thick soap foam for washing cars these days.
I don't quite like the Petro Canada car wash because I believe that it takes longer to accumulate points and also the cloth splashing system could be bad for the car. I was afraid of scratch marks made by those splashing cloths in the car wash.