I thought GF always offered 2 week free trials? They used to anyway... a deal is when you can find a 30 day free trial. As others have said, with a 2 week free trial, if you plan on cancelling before they charge you, you will probably only get your initial shipment of games, and have them available for about a week. Turnaround time back and forth takes just about a week usually. And they do not prioritize the games you put at the top of your queue, they will send whatever they have available, even if it means sending the bottom game on your queue.
That being said, it's not a terrible service or a terrible price, they just don't have the infrastructure to have service as good as Netflix, which they are modeled after.
(edit) Heh, side note, for me, this page has a Gamefly banner ad at the top of the page as I type this...