I have to say, reading a lot of the reviews on the Zune had me questioning what exactly these people were doing. For instance, this article on Engadget implied the zune was a horrendous experience. Obviously I had to get the Zune just to prove Engadget wrong (ok...I wanted one...they look very cool).
Look & Feel
First, the styling of the Zune is, in my opinion, much more refined than the iPod. The iPod hasn't fundamentally changed aside from adding a couple of colors - yay - since it's inception. On the other hand, the Zune just feels nice. Many others have commented on this, but the sort of rubberized (very "sort of") plastic feels good to the touch.
Installation Experience
One word: flawless. Of course, that excludes the minor hiccup I got when it was trying to access an external URL while my internet connection was going up and down. That aside, the software was installed and all of my music was transferred between 10 and 15 minutes. On the other hand, when I tried to dump my existing WMA library on the iPod - it said it would take 3 days (yes, DAYS) to convert them all. That experience left a very bitter taste in my mouth for the iPod and required the purchase of a third party tool, Anapod Explorer, to convert the library in a reasonable period of time.
Using the Zune
The navigation interface is much more attractive and more informative than the iPod. I can do things like view other songs on the same album as the currently playing song, view items on the device in a more organized way and so on.
The one downside I would say is that the Zune host software is very...functional. While it gets the job done, it lacks a lot of the polish of say...the box the Zune came in. They really needed to do quite a bit more work here, better yet...integrate it directly into Windows Media Player. That was just a dumb idea.
Now...off to plug in the XBOX HD player and test the Zune on that!