I was very excited & on the launch day of Galaxy S3 I bought the phone. After using phone for 2 days, people start complaining me about the voice quality issues of phone. My friends said that it feels like I was calling from Speaker phone. When I showed this to showroom guy from where I purchased the phone, he suspected about sim problem. So we replaced the SIM but after some time Voice in handset earphone stops coming when making any calls. So I was directed to take the handset to service centre.
After some inspection, they agreed with issues and replaced the handset within 2-3 hours. Now my new phone is working fine. Thank god the problem occurred so earlier so I got new handset otherwise I have to take the repaired handset