Yesterday afternoon, I noticed the screen to schedule the time of the update and I went with the suggested 2am. This morning the car was charged and the software updated successfully-- pretty painless.
My favorite two features of the upgrade:
1) Google maps live traffic can now be turned on.
2) You can set the energy usage window to look back 30 miles instead of 5 miles. That is really useful because now you can understand why the projected mileage (which is also a 30 mile look-back) moves up or down as you see relatively high or low energy usage scroll off the left of the display.
Good job, Tesla! Now please, please add the time to start charging feature (like on the Roadster) to the next firmware upgrade.