I have Blockbuster online rentals, which gives you 3 movies at any time plus 2 free instore rentals every month, which I use for games. Gamefly seems like a bit of a rip-off, I mean how many games can you rent? As it stands now I've already rented more than what's worth renting and generally just get random crap for the sake of not wasting the tickets.
My friend has it and is lets me borrow some of her games, so I think its a seriously great system! Esp. since right now I am playing Trace Memory (aka Another Code) for the DS and it rules!