Kit Kat (4.4.2) hasn't destroyed my Galaxy S4 but it has certainly diminished my view of Verizon's technical prowess
Google search is a great resource when trying to resolve technical issues, and while Kit Kat has it's share of issues none of them are insurmountable and more importantly none of them have any real effect on connectivity; like many on this forum my Galaxy S4 has been on the receiving end of 4.4.2 and suffers many of the same connectivity issues, and they have been both incredibly annoying and at times supremely frustrating but it is not the end of the world.
I have spent much of my free time of late trying to run this problem to ground and like many of you have tried all of the suggested solutions except for a new SIM card and/or exchanging devices (warranty/insurance), and have had absolutely no success, the one thing that does stand out in the countless hours spent trolling the internet is that this is an exclusively "Verizon Problem" in that nowhere have I found any evidence of this being a widespread (global) issue among Galaxy S4 users; I can only conclude that this is not an issue with Kit Kat (OS/Software) or with the Galaxy S4 itself (hardware), but likely an issue with the firmware that tells the radio how to interact with Verizon's network.
Google develops the Android operating system (OS/Software), then Samsung tweaks it to work with their devices (the Galaxy S4, etc...) by writing drivers and basic firmware and finally the carrier (Verizon, et al) brands it (splash screen, bundled bloatware, etc...) and fine tunes the radio firmware to their network particulars; and here is where Verizon has let us down by releasing an update containing shoddy radio firmware (Kit Kat 4.4.2), now that in and of itself doesn't bother me because it happens from time to time (Microsoft or Black Berry ring a bell?). What irks me to no end is when a carrier is unwilling to man up and say "Yes, we bodged it up but we are aware of it and working to fix it.", I don't blame the tech support people for this as they are not the numb skull network engineers who bodged it up in the first place; they are only here to help the hopelessly inept user and to troubleshoot the truly defective hardware (broken screen, water logged, etc...), so even if they knew what the problem was they can't fix it.
Sadly we have little recourse, we either grin and bear it in hopes that they fix the issue sooner rather than later, take our chances with a replacement device of the same or different model or flee to another carrier and hope that they don't bodge it up too; at this point I would suggest that if you are one of the many who suffer from this issue that you make your complaints to Verizon loudly and publicly in hopes of shaming them into action, and perhaps demand that the head of the numb skull responsible be placed on a pike in front of Verizon HQ.
I am still running 4.3 because of all the horror stories I read about this update for my Samsung galaxy s4... same deal for a lot of the apps I use. I never let it auto-update, & always check out comments, hence my continuing to use some older (more reliable) versions...
I accidentally hit the download button for the android update once (a while ago), and even deal with it wanting to update every day. I just postpone it every day & will continue to do so till the next version (if it seems ok after those on the bleeding edge check it out)
I am on my third s4 in three weeks because of overheating. The first fried itself into oblivion. The second overheated, and would shut down. The current one is 48 hours old, overheated 5+ times on my way home from work after having it for 24 hours...and fried the sim card reader.
I had a loaner S3...24 hours after having it: boot loop.
The entire S3/S4/S5 line is defective. Verizon is insane for letting their reputation turn to sh!t because they are ignoring it, and insist on replacing like for like (S4 for S4), and enraging their customers. I have BEGGED every day for TWO WEEKS for a replacement that is NOT another S4.