Hey Andy, welcome to the world of Nintendo. Hope you enjoy the forums. =)
GameFly definitely has it's perks, and also has a half price for the first month you can take advantage of regardless if you want to have it or not. My experience with them a few years back is that they ship their games lightning fast, and if you're ever worried about spending big money on a new game you might not like, GameFly lets you bypass that risk entirely.
Last I checked, if you really like a game you get via GameFly, you may be able to buy it on their website (if the game isn't in such high demand that they're out of stock) for the average going rate of the used game in question too. That way there's no risk in buying a used game that's too well used to work via an online shopping site or even in-store at a place like Gamestop.
And since it's a monthly payment, you can cancel at any time. The only reason I don't have it anymore is because I'm broke. If $20~ or so isn't a problem for your wallet, I can certainly recommend GameFly to ya.