Yes, I've had the same problem as well.
Bought my S3 in June 2012, and started having problems with my S3 last week. All of a sudden, I found that my phone was hanging 10 - 30 times a day, forcing me to reset the phone before I could use it again.
I sent my phone in for servicing last Friday, and got it back yesterday. The counter staff explained that they reinstalled the latest firmware for me (which apparently has not been released OTA), and said that that will fix my problems.
Did it fix the hanging? NO.
It started hanging this morning again, and I suspect that there is a hardware problem they did not address.
FYI, when I was queuing to service my phone, I met another customer who said that his phone had already been serviced once but was still hanging.
There are links to XDA which report this issue, but I can't post the links. Google for **Ultimate Galaxy S3 Unusual Freezing Thread**