I really didn't like gamenzflix. They hardly had anything in stock. Took them a lot longer to get new releases.
Gamefly has its distribution centers in California, Pennsylvania, and they are going to open another one in Florida.
A week is about the average turnaround for me too.
Some post offices are equipped with special equipment that lets Gamefly know you have put your game in the mail, and they will send you your next one before they actually receive it. Sadly, my post office does not do this.