One thing I noticed every time I opened the iTunes Store was that text would overlap when the home page was loading. Not a big deal because once the page is loaded its fine, but kind of annoying. Other than the design of the store, one big thing they changed was the format of the list of songs, movies, apps, etc. you get when you search something. It's not at the bottom like it used to be and instead of having to go to the top to preview the song, they have a play button the pops up next to each song when you roll over that area. It's a nice feature, however, first time users don't know the roll over play button is there until they "accidentally" roll over that area. It took me a couple minutes to catch on.
Also, they changed the feature of being able to extend the area where the songs are listed to see the entire song, artist, album, etc. Instead, if the box isn't long enough to show the entire album for example, the album is linked and once you click on it, iTunes will take you to a list of songs on that album. That's nice, but sometimes I just want to read the album. To fix this, when you place your mouse on the text, a window will pop up and show the entire text. This happens because of the link. This is kind of a pain in the butt. I think I preferred the old version over this one for this feature, but they had to change it because of the new design.
Other than that one change (I guess I'll have to get used to it...) I really like the new version and design of iTunes. The changes they made were good because they weren't so drastic that users wouldn't be able to find anything. When revamping or redesigning a designer always has to take into consideration the customers and/or users and how the changes will effect them. Just because something looks "pretty" to you, doesn't mean it's a good thing for everybody else.