Since I first got a Zune (30 GB version), I've been a fan of them, mainly for being something other than an iPod that still works great, doesn't break easily, and looks good. One day though, my 30 GB was running low on space - I felt I needed to upgrade to an 80 GB.
I got my Zune 80 used, as a gift. I do like it, and it has served me well and still going strong. The interface of the Zune is easy to use. The main screen is easy to scroll though, and one can easily see all the different features of the Zune just from this front page, such as music, videos, and games. The controls are simple: a backwards arrow to go to the previous screen, a pause/play button, then the center pad, which controls everything else by either pushing on one of the sides, or sliding your finger up/down or left/right on it to get to where you want. As for the battery, I can usually last at least a full day on a charge, usually more. This time has decreased over the years, though.
The Zune program itself is pretty easy to navigate, though as a netbook user, it does slow down my computer by a lot, which can get annoying and makes me want to have it open as little as possible.
While I do love my Zune and how durable it is, I do have some complaints about it. Like for whatever reason, all this dust somehow collected inside of the screen, I don't know how to get it out, and I'm too paranoid to open it up to remove it. Also sometimes when scrolling through the songs on shuffle, even though I'm sliding in the direction to go to the next song, it likes to go backwards instead, though I think this is just a problem with mine, like the dust problem. (I haven't heard of problems like these before.) One final complaint about my Zune that is an actual problem with it, and all of them I'm sure, is that sometimes when scrolling through a long list of songs, I'll accidentally move my finger to the left or right, and then I'll have to start over in looking for the song. While I can live with it, it does get annoying.
As a whole, I do like my Zune. While the appearance (the dust) and the controls not working properly, it has been a great device, being able to withstand many drops over the years, and still going strong!