I have my Galaxy S3 updated to Android 4.3 Jelly Bean (SGH-T999, T-Mobile version). I don't really see a problem with it, but lots of people are having lots of complains on the update based on Galaxy S3 and S4 users. Well Android 4.4 Kitkat should be in the corner for you Galaxy S4 users, if you worry about the problems on Android 4.3, then wait for the Android 4.4 update.