Full disclosure: I worked at Amazon this summer, for those of you who didn't know, and I was not a part of creating the new mp3 store or the new site navigation. I did see the new navigation, and had some time to play around with it, but I didn't actually tell anyone about it or blog it, for that matter, because it wasn't public.
Amazon finally opened their music store, and I was pleasantly surprised. My earlier impressions of it were that it would end up being an unfortunate mess, but I think they've really come a long way since what I had been hearing about it. All the music is totally free of DRM and features UMG, EMI, and tons of indie labels. The only reason they're missing Sony BMG and Time Warner, I imagine, is that they haven't let go of DRM yet.
There are a few reasons why I really like it and have faith in it. You can basically download the music from anywhere, you just need a browser. Strangely, you need a downloading tool to get an entire album, but this is nice because it doesn't require additional software (though I wonder if Amazon is working on an iTunes-like player to supplement this) to get a random song. This means that smartphone users could probably download music from Amazon MP3 and sync with their computer later, so this would even better compete with iTunes. I like how easy it is to preview tracks: you can forward through them after hitting "Play All", you can hit the play button next to each track, and it's much more responsive than iTunes is. These previews aren't just available for an album or artist, they're for search results also. The pages overall are clean, and the album pages have direct links to the CDs in case you want to buy those instead (the CD pages now have the same preview functionality, much better than what it was like before). To top it all off: the top 100 songs at any given time are $0.89 (with songs usually priced at $0.99) and the top 100 albums are $8.99. Overall, it's an easy shopping experience.
There are some problems though. For one thing, if albums can cost as much as $11.99 (maybe higher, I haven't browsed thoroughly), won't they be as much as the hard CDs? Then all you're saving on really is shipping. You can't re-download tracks once you've bought and downloaded them once, which isn't that big of a deal since it's not like you could on iTunes and if you could then you could just give out your account information to friends and they could all have your music very easily. I'm sure they are tracking your purchases for recommendations though, which is another thing they should flesh out more (and knowing Amazon, I'm sure they are). Why do we need software just for album downloads? That's weird. It's kind of like Down Them All: it only appears when you click to download a song or album. It sounds like bad design, to be honest, that you can't download full albums from the site, but maybe there's a better reason or maybe it's something they'll hammer out now while in beta.
Why are their odds good? They're Amazon. They have a huge brand name, they have really smart people, and they can probably personalize, recommend, and cross-promote stuff better than iTunes can without being obtrusive and, hopefully, while staying fast, convenient, and cheap. I think they're very well aware of the business model, so I believe in them.
I have to go pretty soon, but real quick: Amazon has started a Web Lab for their new global navigation. Basically, only a portion of visitors will see the new design, and they'll use data from these visitors' clicks to determine if it's good or bad or needs tweaking or what before they roll it out. I was at first very stubborn about the new design, but it didn't take me long at all to embrace it whenever I went back to the current Amazon site. It makes a lot of things better and easier. You always have access to the entire site in the corner of the screen, the top bar gets a lot smaller, you can see what's in your cart without clicking to it, etc. They put a lot of time, thought, and effort into this design, so don't discount it as some overnight impulse change or anything. They're really focused on making the site easier to navigate, faster to use, and more visually appealing. If you manage to see the new site, definitely play around with it. In my opinion, it's their largest overhaul of the UI since Amazon.com first opened its doors over 10 years ago, and it probably actually is.