Just got a chance today to try the version 5 demo and I love the new features. One thing I noticed was that when I had albums that had only one track, such as singles, that when you selected them from the album screen it would bring you to a screen that looked similar to the now playing screen and at the bottom were the play options. This is fine (guessing that it was a new design feature for version 5) but when I click the album art that is showing or the back button it takes me to a history screen showing the history for that album. I can then go back to the main album listing screen. Don't know if this is a bug or not. Just thought I would let ya know. Also with these single track albums the quick jump covers for albums by the same artist don't show up.
P.S. Albums with more than one track do not do this and go right back to the album screen when I hit back.