We are certified installers for the Tesla Power wall and have installed one in our offices.
Our office installation was two fold , in keeping the office supplied with power at all times and storing our solar energy to use through the evening along with using it as a live installation that potential clients can view.
Since installing, we have found the extra value adding software management system that runs the system has been astounding to say the least.

We have permission from our local municipality to feed back to the grid and have a 4 quadrant net meter installed by the municipality which we can access on line.

We have a 3 phase supply coming in and the Power wall is on phase 1 - If we run a vacuum cleaning on phase 2 the power wall injects back into the grid on phase 1 to zero the usage on phase 2. This is a setting during commissioning and can be changed.

The Power wall allows us to set the % of stored energy to use for self sustainability and a % of stored energy to use if the grid falls away.
It also has a setting to use to cover the peak tarrif times which is where it starts to pay for itself.

At 13,5 Kw of potential stored and usable energy it is price competitive with other battery technologies.
The added advantage is that there are no gases , extremely quite , and no DC cabling that needs to be checked on a regular basis. Used in self sustainable mode with Solar it has a 10 year warranty at 70% capacity in 10 years.
The App on the phone is easy to use and monitors the different energy streams.
When I look at the specifications and what we are seeing live , the Capacity and Power , Round trip efficiency , Depth of Discharge , Battery life and warranty , it is hard to beat.