Two days of driving in the Seattle rain. Highly variable wiper reactions. In the light rain we've had the last two days the wipers don't activate at all in switch position 1. However, on position 2, in daylight, they activate reliably, a little later than I prefer, but still pretty good. But at night, on dark roads without any street lights you could be in the ditch before the wipers start working. As soon as I get back on a moderatly to well lit road the wipers start working again.
All in all I'm happy with this release and plan to always leave the system in the "auto ON" switch 2 mode for normal driving. If the wipers don't start when I want a clear windshield, it's a simple matter to select Settings>Vehicle>Auto Wiper>OFF and since the wiper switch is already in the number 2 position, the wipers will immediately begin working manually. Simple enough to do until the system is further refined by Tesla which I hope it will be eventually. Nice update.