We recently installed an 18 panel 6120 watt solar array sold and installed by NuWatt Energy.
http://nuwattenergy.com/ It was a professional and hassle free install. 30% federal income tax credit and the NH rebate of $2500 were a big plus in our decision.
We heard about them through
http://solarupnh.com/ in a presentation in Derry NH.
I talked with Solar City over a year ago and was not impressed with them. Their leasing option was not worth the $$. Plus they would only install a 4400 watt system and that was not close in size to what we now have and own.