Do not rush in selecting the first solar power system you come across. Before you make a commitment with a company, you need to make sure you cannot find any better deals elsewhere. Check out your town's federal, state, and local incentives first. You can find this information at the DSIRE database.
Be prepared to keep your solar panels clean. The dirtier they get, the less efficient they are at generating power. While it is true that rain and wind can often take care of a lot of this for you, you do need to get up there sometimes and dust them off yourself.
Testing at around -20c, amazing results.