Last summer we had the task of choosing a company to build our new site
http://timberbuysell.com. Since the software model is basically a classified ad system, I suggested using off-the-shelf instead of custom programming. I researched about 12 different products.
Would you believe that several of the companies had "our customer" links that were broken. One "happy customer" said that the software "sucked" when I contacted him and recommended another product. I did find one where all the customers I called said good things; so we used their product and have been very happy with the product and their service.
Due diligence paid off!!!