Which update are you talking about? Latest 4.1.2 are all stables and work fine. If you want something really fast, I'd say it's best to try some custom roms based on AOSP.

 

Are you rooted?

 

There's no date on when 4.2.2 will be officially pushed out, in fact I just read it may have even been delayed so the update notification you're seeing will be 4.1.2 still, just tweaked.

 

Did you try a factory reset?

 

If this happens, it is not the problem of the upgrade. In fact, it appears to be quite stable. You need to investigate other issues with your phone, including misbehaving apps. I suggest that you "clean" the device and carefully observe the apps that freeze or force reboot.

 

Absolutely.

If you're downloading paid apps for free, its entirely possible they're riddled with malware.

I'd suggest downloading from Google play store whenever possible, or another reputable app store like Amazon's.

 

Its very possible its the apps but, when i had the same problem, lag and freezing i needed the motherboard replaced. Never happened since. Might be worth booking a repair.

Phone was back within a week.

 

I updated my phone with version 4.2.2 from a link on this website, it runs flawlessly with no issues, although there isn't a great deal of difference in the update (or I haven't discovered the features yet!) Phil
http://forum.xda-developers.com/showthread.php?t=1835931

 

That's a test release bud so some features won't be present yet (mainly S4 stuff)

Personally I've had trouble with the Gallery in that it contstantly Force Closes on me but that led me to the QuickPic app which I much prefer anyway.

Other than that minor issue I like it too, can't wait for the final full release