A "golden nugget" of information is reported in Business Week's Small Biz Feb/March 2008 issue. In "What's for Launch" Doug Hall, small biz guru and CEO of Eureka Ranch looked into the issue of determining whether to go ahead with a new product launch. I'm often asked questions about new product launches, e.g., how to decide whether to launch one product over another or to launch at all.
To answer this question, Doug Hall looked into his data archives of 100 product launches by his clients and academic articles to see if he could offer an answer. He found that the single best predictor of success was meaningful difference or uniqueness. Meaningful difference in this case refers to a blend of customer interest in buying and perception of how different the product is from competitors.
The big takeaway here is that the marketing task for any product or service is to tell customers why it's not the same old thing. There needs to be a real answer to that question, not just spin. That means that if you are struggling to find the difference, or there really isn't one, reconsider launching it until it has one. If you spin the product to appear to have a difference when one doesn't exist you'll get returns and unhappy former buyers.