Maybe this should be a new thread but I will throw a few things I have noticed with the S3 at this time.
Bluetooth - No issue pairing or with signal, but when paired with my VoyagerPro HD, I have noticed that answering via the headset button actually hangs up the call. More to come on that one.
Optimizer WiFi/EVDO/LTE - I am so used to having a button for 4G on/off and that was removed. I like the auto network selection but I would prefer to be able to take control of LTE at least for testing (assuming you have a Network Vision/LTE groomed tower). If there is a way to do that, I haven't found it yet.
Lock Screen Options - Facial and Voice unlock features are a little flaky, however, the voice interpretation for typing seems to work extremely well compared to my Epic Touch.
EAS Native Client - Still doesn't have the functionality I need to use it. Reverted back to Touchdown
SmartStay - Works really well but varies depending on the angle and lighting
AllShare Play - Awesome
S-Beam - Works great, still comparing battery consumption of NFC
PIP - Excellent feature
TecTiles - Awesome but the standard app native to the device is not nearly as robust as some of the aftermarket ones available
GPS - Auto GPS is great and seems to work really well. I have not had any issue with the GPS not connecting like the Epic 4G
Motions - After you learn them all they seem to work very well, I am comparing to see how much power they are consuming
Battery - Excellent, after using the device for 7 hours straight, auto brightness, 2.5 hours of talk time, I had 30% left.
The one thing I would say is that I could not give this device to my wife without a training class. The touchwiz software is extremely robust but almost gives too many options for a standard consumer. Samsung should ship this device with a tutorial DVD.
Oh and the native ringtones suck. Like a spa day or rain forest theme, blows.