My son (9) subscribes and we really like it. We have saved a lot of money by being able to try games this way. It's amazing how many games aren't nearly as playworth as you'd think. Now, even if my son isn't crazy about the game, he'll play it for a weekend and send it back for a new one. The ones he falls in love with, he puts on his Christmas/birthday list or saves his money in order to buy it himself.
As MarkBarbieri says the turnaround isn't as fast as Netflix, but it is still a value to us.
Kerry