In my biased opinion, I thought the interface was better than the iPod and I've heard the new ones are even better. The best part about it was the fact I didn't have to deal w/ Itunes. It would let you upload a ton of different audio and video formats and download those formats to any computer. Really nice for DRM free content.
Unfortunately it was stolen a couple of months ago so saving up for the new Zen X-fi 32Gb.
I have a 4gb Zen Plus V, Sansa Fuze and a Zen 8gb. I use the Plus for the line-in to record Sirius, but the player controls/screen are too small for comfort.
The Fuze is solid and looks good. Smaller screen than Zen, weaker interface. The breaking point is the sound. The Fuze isolates a treble sound that gives me a headache. Couldn't fix with equalizer.
The Zen is excellent. Reviews will tell you so and are spot on. Don't be turned off by the non-integrated SD card. Access is an extra click away and music that isn't recognized by the internal library will often play off the memory card. Great interface, battery life, graphics. Like I said reviews are correct.
My Creative Zen Micro has been just ok. But it has had issues when I was using Yahoo Music and would require pulling the battery every once in awhile. Now I have transferred a bunch of songs to it, and some of them have strange digital distortion at unexpected moments. It actually sounds like it's injecting another song for a split second in the middle of a song. But this is an old player, so I doubt this would be a problem with a newer model. But it still makes me think getting a zune would be a better choice for me.
I'm on my second Creative player and I love it. My first one was the 20 GB Zen Jukebox which was ahead of it's time when I bought it about 5 years or so ago. I definitely had some problems with it, but most of them were due to the organizer software which was absolutely a mess. I spent most of my time trying to find a sync method that I liked! Now I have a Zen Vision M 30 GB which does everything the ipod does but without itunes, which is a big reason why I have it. The Vision is really nice, the interface is very easy to use and the screen is awesome. Of course it sounds good too, and the battery life can't be beat. It integrates nicely with WMP or there are other options too. I think for the money you can't go wrong, though I don't know what their current offerings are now.
The Creative devices are nice, but their support is terrible! I had Zen Vision M, but actually opted to return it. I know folks say it can do everything the iPod does and that is probably true in terms of other iPods beyond the iPod Touch, which is actually what I opted to go with. Mainly because of the accessory availablity!
In terms of the Zen it was well made, had a beautiful display and in terms of providing great play of music it did well. I found it was a pain in the ass to manage album art and of course no gapless playback. But a solid device non the less! They are usually priced right and of course the Play For Sure if you have an unlimited music service is just fantastic.
I've done a lot of research on them and almost bought one several times. I've avoided other MP3 players because I just don't need one--I have the stiletto 2 and that is fine for me.
The Creative Zen is a great player with a FANTASTIC screen that plays video very well. The user interface is good, not great but it is very easy to pick up and learn.
The only real negative that I have heard is that the SD Card slot is HORRIBLE. If you use a card to expand the memory, it does NOT integrate into the library that you currently have on the player.
That is the only real negative I have heard of and may have been resolved with a firmwear update. I know they make up to 32 gigs in the ZEN so assuming you don't need to go higher than that, you would be happy with the player.
If you're still deciding, check out the Samsung P2--this is a sexy MP3 player with more options that almost anything out there except the IPHONE.