The downside is that all these apps will only offer rather basic functionality. Don’t expect GNOME music to offer fancy graphical equalizers or sophisticated MP3 tag editing. Its job is to simply make your music collection nicely available to you, and play the songs you wish. My personal experience? I never really liked the Unity desktop. In fact I preferred Gnome 3 over it. If I had a choice I would rather go with KDE (or a derivative of Gnome 2 like Mate / Cinnamon) instead anyway. Perhaps I’m just biased, I also don’t particularly like OSX’s UI, some parts of it just feel as if they’re random thoughts instead of a consistent design (much the same way I feel in Unity / Gnome 3).
For this reason it’s a complete Meh in my case. As far as I’m concerned I felt Ubuntu/Canonical was wasting their time on this want-to-be-both-desktop-and-mobile schizophrenic OS. Gnome 3’s closer to achieving it in any case. Though both are running into the same troubles Win8 had – where some features are more apt for a touch interface than a mouse. I couldn’t care less, except that perhaps Canonical can now afford to spend more resources on making the complete OS even better instead of trying to make some hybrid UI which never worked well for me.