It was available to me too. Have not pulled the trigger. It's the same software version that is on my G4 and there is no new info on the Verizon support page. Anyone try it yet?
I just installed it, was really small. Quick install, 5 to 7 minutes like it promised. Booted up with Wi-Fi connected, been up 10 minutes now. Baseband version shows up as I545VRUEMK2. Still Linux kernel version 3.4.0, but Nov 20 2013 compile date.
I downloaded it and said install, but it failed on my completely stock S4 and left me at the bootloader screen.
rebooted and am downloading again for a second try.
My wifi is definitely better. Previous update back in October "broke" or severely limited my ability to connect to wifi which had strong signals before. It seems to now be back to where it was prior to the October 4.3 update.
I'm still seeing it drop the Wi-Fi. Sometimes it say's it's stuck on 'obtaining IP address'. Just now the Wi-Fi turned itself off. I'm getting ready to ditch wi-fi. This is crap.