Home Green Products Guide Which things to look for while purchasing solar power systems for home?

Which things to look for while purchasing solar power systems for home?

I am planning to get solar power system installed in my home. I was just wondering if some expert can help me out with what things to look for while purchasing solar power systems for home. One of my friends told me that sizing it properly can be a tough job. He has solar power system at his home. So can somebody enlighten me on the features to look out for and even the drawbacks to watch out for while purchasing the solar power systems for home? Please give valuable feedback. Thanks.