EnergySage is the best vendor marketplace that I have yet to experience. With about 5 minutes of work on my part (entering in details of my home and uploading a pdf of my electric bill), I was able to get several preliminary quotes for adding solar panels to my home. The interface made comparing companies easy and the knowledgable EnergySage representative was able to answer questions and help me dig into the differences between offers. Anyone with a serious interest in contracting with solar companies is doing themselves a disservice if they are not using EnergySage.