I bought one on my VT50. I hope it breaks this year and is irreparable so I can pay pay the difference for the ZT60 or F8500.
I didn't get one on my last Panasonic plasma, which I sold to a friend, and it still works (it's a model from three years ago). I only had two problems with it: 1) The batteries inside the original remote exploded -- leaving dried battery juice all crusted up inside the remote by the time I discovered it. Yes, they were the original Panasonic branded/supplied batteries. 2) The Smart TV functionality just quit working. Really odd. I didn't really care, since I never used it. Pressed the Viera Cast button, and the screen would like it was attempting to launch it, but never did.
Ask yourself if the peace of mind is worth it to you.
ht Panasonic TC-P60ZT60, Monitor Audio: Silver RX6, RX Centre, Radius 90HD; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D
2ch Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Monitor Audio Silver RX1, REL T3, Apple TV, Peachtree Audio DAC•iT
lr Panasonic 50ST60, Sony BDP-S5100