From my past experiences with Android smartphones on VZW, there is the possibility of certain amount of pain from updates as well. On every OS update I've taken from Froyo to GB to ICS to JB, I've ultimately performed a FDR on my phones and found that it eliminated many if not all of the bugs that surfaced from overlaying an updated OS on top of the old one. It can be somewhat of a pain to do an FDR, but in the long run it can eliminate a lot of headaches and allow your phone to run much smoother. It would be nice if Kit Kat and future updates go smoothly without the need for a FDR. Here's hoping!