Seth Godin recently pointed out you can differentiate on three different bases: results, thrills or ego. 

Blog: Three things clients and customers want, 2011-Aug-16, by Seth Godin

It's tempting, particularly for a small business, to obsess about the first—results—to spend all its time trying to prove that the ROI is higher, the brownies are tastier and the coaching is more effective. You'd be amazed at how far you can go with the other two, if you commit to doing it, not merely talking about it.

So remember:

• Thrills tap someone's emotions and imagination.
• Playing to ego means making customers feel important.

So don't forget you have two other ways to build loyalty even if you providing a parity product.