I told a salesman he could come over and pitch his solar electric system. Can anyone give me some real world advice?

Is it worthwhile? Do you ever make back your investment? What type or brand is considered the best or most efficient? What questions should I ask? Do they need maintenence, like cleaning? Buy or lease?

Sorry for the shotgun approach, but I know very little about the real world viability of a solar electric system. Years ago I went for a solar water heater, and it never paid for itself before becoming problematical.

I do have a roof that is large enough and situated well for solar panels, and I live in SoCal.

Thanks,
Rick Potter