Sorry for not seeing this sooner, I took a bit of a break.
To be honest with you, I never even tried it. As soon as I tried to put my phone in the first time, the mount went back in the box and back to AT&T. I feel like I should have been more vocal about it, because it really does not fit. You have to force it in, and I just was not comfortable with that as a long term solution.
Samsung really needs to step up to the plate here. It's not rocket science. I bought four S3s for my family in large part because I knew this would be the most popular phone to come along in a long time and I assumed that meant Samsung and the aftermarket would take the accessory situation seriously. I rely heavily on my phone to run my business and when it comes to day-to-day usability, the phone itself is only half the equation. So far I've been pretty disappointed, but I guess I have no one to blame but myself for assuming.
At this point I'm back to having an ugly ass metal flange sticking out of my dash just waiting for somebody to make something that works.
As an aside...
Apple has never gotten a penny of money out of me, and I really disagree with many of their philosophies, but I'm seriously thinking about switching. I'm almost willing to put up with their BS so I can have some accessories that work. I love Android, but there truly are advantages to having a fairly homogenous hardware platform like the iOS devices. If there was one thing I could change about Android, I'd go back to day 1 and have Google mandate a common connector and position thereof. MicroUSB is fine, but if it was in the same place on all devices, it would be a lot easier to design accessories.
This sort of thing just shouldn't fly anymore.