Had a 6.375kW system installed on my roof. Twenty five American made Suniva 255W panels with Enphase microinverters. Microinverters allow each panel to operate independently of the others to partly counteract shading. I expect shading to increase as winter approaches. I predict this will affect the panels lower on the roof more, but the price jump to put those 3 extra panels was not really significant in the big picture. Almost added another row even lower, but I think that would have crossed the point where it would not really be cost effective, particularly when you look at the long term. The system is bigger than I need both because I want to get a plug-in hybrid in the future and because MA pays out SRECs for each MW generated. SREC market is at the floor right now, but it is still cost effective, I think. Company was very professional and overall did a great job. There were a few delays and set back, but that is to be expected with such a large, complex project, particularly where multiple permits, rebates and other incentives are involved. I expect the break even point to be around 7-8 years.