I totally forgot they had OFP.
Just be wary that they rotate the free games every couple months.
I've had a paid account for a while. I got it when they had a deal that your first month was only .99
I love the fact that If I have a premium account, I can set up 5 sub accounts that can be played on any computer. You can set parental controls on these sub-accounts if you have children, since they have a lot of child friendly games too.
They used to have an application that you downloaded to get the games, which I preferred to the browser thing going on now.
When the first brought on the browser part, and got rid of the application, there were a lot of problems with it not running properly, And they coulnd't get it to run on 64 based OSes at all. But they've buffed out these problems a while ago.
There is still a game here or there that wont run on Vista+Windows 7, but these are games that don't normally run on 7 or vista unless you tinker with them.
The one main problem with Gametap is you can not modify the game files at all. Which means no mods, and you have to use whatever patch they have running. Which means some games aren't always up to date.