You mean their reward scheme in its current iteration?
If so, I'm currently a Silver member and they debited my account for Assassins Creed 3 just yesterday. It's being sold at £39.85, but I get £1.49 'cashback', thus technically making it £38.36. I wouldn't really call that much of a difference in price.
I'd rather they just gave the best price, instead of accumulating 'reward' money. Like I said though, now they have become big and get pre-order bonuses, they no longer need to be really competitive with their prices like when they were a small retailer.