The only thing these guys want to do is get pannels on your roof, after that, good luck getting in touch with them for anything (general questions, asking about my bill, having to get the pannels off for a re-roofing). I've been cussed at, hung up on, promised a lot of call backs but I get nothing.
THEY DO NOT CARE ABOUT THEIR CUSTOMERS ONCE THEIR PRODUCT IS ON YOUR ROOF.
If you plan on going the 30 years or so without calling them for anything (or wanting to easily see your bill), then go ahead. But I'm sure within 30 years you will need some contact with them so be warned...