Jon Udell - First have a great use experience, then have a great user experience:

"We talk obsessively about the user experience, and we recognize that we invariably fail to make it as crisp and coherent as it should be. But user experience is an overloaded term. I propose that we unpack it into (at least) two separate concepts. One is the basis of the “aha” moment. For now I’ll call it the use experience. In this example, it’s the experience of listening to spoken-word podcasts from sources that, just a few years ago, weren’t available."