I generally prefer owning games, but my friend tried subscriptions for both gamefly and gamesnflicks (which is quite possibly the worst name ever). Basically GNF was cheaper, but time in between games and game selection wasn't great. Gamefly was good when it actually worked - and when there were issues it fell on its face.
For example, there was one instance where he got a broken game - literally broken - in pieces. So he was worried they'd think he did it, so immediately contacted them, and after going through the customer service crap, got them to accept it. But apparently they wouldn't send out a new game until they received and confirmed the game's status. This took a week or so, and they wouldn't give him any free time or anything like that.
Also since you're in NJ like myself, I'm pretty sure he said the center is in California - and at the time there was only 1, so shipping back/forth took a week each way. After a few months waiting times started to increase (as per Netflix), and especially after that broken game incident he canceled it. Now the bum just leeches off of my old games. Ha.