There are many different inspectors, all with different qualities.
Inspectors who are licensed contractors are the most qualified because they have experience in building and repairs. They are certified by the state rather than an inspector who is certified by some association which they pay to be members of.
Objective inspectors work better for the home buyer. Many inspectors are just as interested in getting the deal closed as the seller and agents are.
Check out these 2 websites for more information about choosing an inspector: www.BuyersProtectionService.com/ChoosingInspector