Ask your neighbors with solar who they used and if hey liked working with them, and also get a lot of estimates from lots of local contractors. You will see all kinds of system proposals when you do this. Go with the contractor that you like dealing with who has a good system proposal. A good sign for me was when someone was willing to make changes; eg, use micro inverters vs optimizers for my complex roof geometry.
You can't figure out who's good online, interview the local companies. Locals will also get you through the permitting and code compliance process too.
Also, don't overlook the "services" category of CL (e.g. https://sfbay.craigslist.org/search/bbb?query=solar%20instal... it still carries the same "call a rando" risk as does hiring any contractor, but it can be easier than filtering out the higher budget Yelp businesses. Sometimes they list in the for-sale category, too as CL is wont to do
You can't figure out who's good online, interview the local companies. Locals will also get you through the permitting and code compliance process too.