I also looked into this right after the NY Times ran an article (“Here Comes The Sell” 8/12/12) on the trend towards renting systems to homeowners.
I got a quote from one of the big outfits. In the end, I decided I didn’t want to trade away my federal tax credit (30%) and utility rebate (varied by company) in order to have them installed “free of charge.” Turned out I’d be sending a check to the solar lease company instead of my utility. Their projection on the increase of electric rates seemed a little inflated. We concluded it’s best to buy them outright if you have the cash. Our monthly electric bill was too small to make the ROI pencil out– for now.