One thing Solar City has going for it is easy access to Tesla's excellent battery storage products to integrate into their offerings. Charge during the day, use during the night.
I don't see SunPower offering an integrated energy storage component for their residential systems on their website.
Since Solar City is an integrator / installer, not a manufacturer of solar panels, it would make sense for Solar City to offer "best of breed" components as an option, offer SunPower panels for power, Tesla batteries for storage.
this is a huge market and pretty much 2 big installers scty and spwr I believe ther is room for the chevy and the cadilac scty owners pay attention to and hold up their stock price spwr does not but it is the best there is at this time. they also go against fslr I also believe that spwr really kicks fslr asskk. so in this company rooftop is fine along wit scty. in in power plants it seems to be much better. the hitmen keep tellin ya that fslr is makin money and spwr aint they say that a lot now cause next quarter they can t also they will compare full year anything to paint a false picture. don t understand why. it may be they are so used to bein sheetheads for the last 4 years that they can t do anything but trash companies. I guess that would be green glasses for jealousy. anyway this company is the bom