It sounds like you're currently spending about $4380 a year on electricity. Ouch.
Assuming your investment (solar + powerwall) covers all of your electricity needs, you're getting a minimum 14.6% return on your investment per year. It's hard to see anything wrong with that.
The only caveat I can think of is that the cost of solar panels and especially the powerwall batteries is likely to fall sharply in the next few years, so waiting a bit might pay off. But it sounds like installation, etc. are your biggest costs, so even if the cost of the powerwall falls in half, you'll make up for it by installing now.