It appears that Tesla/SolarCity estimates for PowerWall installations are quite competitive. And there is something to be said for dealing directly with the product manufacturer rather than going through a third party. Going with a SolarCity bid for both PV and storage could have advantages. On the other hand, I hope and expect that Tesla will prove to be responsive and proactive in serving PowerWall customers who may have gone elsewhere for solar.
As I've partially described elsewhere, I tried going with SolarCity for PV last autumn, paid their deposit, had them come out for a site evaluation, and waited for their engineering proposal. This took several weeks. At this point, however, SolarCity "disqualified" our home; they told me that we have just a bit too much shading for them to agree to install PV on our roof. I was not willing to cut down trees to meet SolarCity's threshold, so we went with another installer.
We used the Pick My Solar platform to solicit PV bids, and went with LA Solar Group. They did a great job with the installation of SunPower 360W panels with micro inverters, plus a service panel upgrade. While not cheap, this setup maximizes production on our limited roof space, the warranty is very good, and there's a first year production guarantee. So far, our production seems to be very roughly on track, but we'll see. Even in our case, PV will pay for itself - it'll just take longer (maybe 10-12 years). From our perspective as homeowners, everything did work out for the best.
From the perspective of a TSLA shareholder, however, I was disappointed that SolarCity walked away from our business instead of simply downgrading the production guarantee to match our shading. We weren't leasing or financing, so this should not have been an issue. My hope and expectation is that as Tesla/SolarCity moves toward premium PV products, they will avoid unnecessarily saying "no" to customers who may be willing to pay a bit of a premium to generate their own clean energy. And they also have a key opportunity to use PowerWall installations to deepen (or initiate) customer relationships.