I would hold off. It can't accidentally get messed up if you don't do the upgrade. Then again, be prepared to do it soon. As I understand it, the firmware also provides updates to play some newer discs.
There are several people on AVS forum reporting lockups and issues when applying the new updates, especially on the A2. Might want to hold on on that if you aren't having any issues to make sure. It was also repoted from Toshiba that you always go in to the management settings and...