So far I've avoided any of the oft reported s4 issues and I have my phone set up and working beautifully. I really don't want to mess with it. Every day I get the pop up notification for the ota update and each time I postpone it. Two questions : 1. Am I being too paranoid? The many posts titled "Since the update, xyz isn't working" are daunting. 2. Us there any way to permanently reject the update this time around so I don't have to keep getting the pop ups?
Download Helium back up. It comes with free version and allow backup of most of your phone. Rest you can do through google and Samsung sync.
The updates are crucial and can prevent many future problem, like the s3 update, which prevented infamous sudden death syndrome. You are far better off spending an hour or two restoring phone from backup, then sending it to service for two weeks.
Helium is pretty good with backing up app data. It really is small effort, considering the benefits the update can bring.
If you are using an unlock unit, I wouldn't worry too much. Seem the problems are more common with devices running telco's own bloatware.