The 4.3 update is awful. I can use my phone only for legacy voice & SMS services. Wifi and mobile internet are unstable, and I'm lucky if I recieve an e-mail in 2 hours... See all the issues here:
Petition to Samsung to fix problems related to 4.3 upgrades - PetitionBuzz
Re: Galaxy S3 4.3 update questions and issues!
I suggest to stop waiting and to sign a petition asking Samsung to solve problems that derived from the 4.3 upgrade.
Petition to Samsung to fix problems related to 4.3 upgrades - PetitionBuzz
and share it with as many friends as you can!!!