My system has been up since August 2017 with few issues. I have two units and 4.1 kW of solar on the central coast area of California. My goals had originally been to minimize power sold back to PG&E due to the very small payback on the rate plan on I was on (buy@ ~20 c/kWH and sell @ ~3 c/kWH). I have subsequently moved to the EV-A rate and found that the utility pays significantly higher amounts for sold electricity during peak and partial-peak times making it more financially sensible to sell back excess solar.
My current configuration uses grid from 2300 - 0700, primarily for charging my Model S otherwise I'm on solar or battery. Currently, I'm seeing enough solar to recharge the batter to 100% by about noon each day so I go into the peak with a full battery and divert all solar back to the grid. We are fortunate enough to live inland about 15 miles as the crow flies so we benefit from the marine layer most evenings resulting in very little air conditioning usage most of the year, perhaps 2 or 3 weeks in the hottest months. Average non-occupied system usage is less than 8 kWh / day. Occupied is about 25 kWh/day. These numbers are for 2700 ft2 home with good south and west exposures.
I have found that the new TBC settings required some tweaking to meet my needs but overall I'm happy.
I think the key takeaway is that the Powerwall, while not a perfect product, is able to upgraded over the air with firmware updates. Absent that capability, I wouldn't even consider any other system.
One last thing; we've had 8 outages since installation. Most have been short, less than 10 minutes, but two were more than an hour. All were seamless to the computer and any other electronics.
I'm happy.
