I'm not a technical expert and have not set eyes or hands on Microsoft's answer to the iPod, but I've picked up two bemusing "facts" online.
Firstly, the Zune is not yet compatible with their much-trumpeted Vista operating system and secondly the benefit of being able to receive tunes wirelessly from your friend's Zune is temporary - after three plays or part plays these tunes are deleted.
It's entirely understandable why both these situations have occurred and as an ardent defender of copyright I fully support the latter, but it seems to me that both offer the potential for disappointment among certain prospective purchasers.
While the ultimate impact that this may or may not have on the success of the product depends upon the numbers involved, I wonder if it would have been preferable to avoid them? Predicting and eliminating sources of negative word of mouth is a vital part of product development.