Yea, I think it fixes a bug with the Phone icon on the lock screen, which would go away and you wouldn't be able to put it back. And some other things I think.
I say test what you have out first. If you don't have any issues then just stick with what you have. I myself probably wouldnt have updated if it werent for not being able to watch Green Hornet without updating. But theres a way to install the watch updates by themselves without updating the entire rom. I noticed the phone was smoother before I updated.
So i installed the update and I can't for the life of me get a "quick link" to my phone application from my lock screen. I go into settings and put it there (the phone application).. but when I go to my lock screen the circle is empty.