Dive summary:

• Adding solar top a rooftop is not rocket science, but it's good to have a contractor's perspective along with an electrician's expertise on the job.
• Inevitably, solar will require penetrating the roof in places, even if just for mounting hardware, and it's a contractor who understands the need for flashing and waterproofing each penetration to preserve roof integrity.
• If a contractor is advising a customer  on solar installation, especially during construction, it's important to keep in mind the need for south-facing – or at least not north-facing – surfaces and the right angles of the panel's to the horizon.

From the article:

The PPA financial model places a premium on equipment selection because it changes going solar from a simple product choice into an investment decision. ...