The only thing I don't like about Zunes or iPods is that they don't play AVI video formats. Thats what I rip my DVD's to, using AutoGK, and it's really good quality, no compression loss. As of right now, neither of those play it. The Creative Labs Zen Vision Widescreen does though. But those are more expensive, and IMO I like the looks and features of the Zune the best so far, (aside from lack of supported AVI files). However, with updatable firmware, somebody could write a patch to read the AVI format.
I hope Pioneer will come out with an intergrated Zune input which (like they have for the iPod now) will control the Zune. When this happens, I will be buying my first MP3 player, a Zune.
My only hope is that a Zune Adapter from Pioneer will directly read the digital files and use the Pioneer HU's MP3 reader and D/A converter. That way, quality will be at best! This perhaps is too much to ask though.
I, like a lot of people, am looking for a solution to have a way to listen to all of my songs without switching CD's, sources, etc, but without loss of quality, in the car.