|Ubuntu Classic Desktop|
Overlay scrollbars comes part and parcel with Ubuntu, so users will get a tad bit more horizontal screen real estate, but it's a new addition to Ubuntu which means not all software uses it yet. Firefox 4 still uses the traditional scrollbars, for example.
New network and datetime indicators have replaced their respective applets in the system tray. If you're running Unity, the old system tray area is no longer there. It's now completely composed of indicator menus. The new indicators are the same as their predecessors feature-wise (as far as I can tell) although things may not be as configurable as they used to be in 11.04. Since it's still very new, I'm sure a lot of software have yet to support Ubuntu's indicator menus so you might run into some trouble with certain apps.
Experimental support for btrfs is available in Natty. It's still too early to use as the default filesystem, but Ubiquity allows installation onto a btrfs / partition without needing a separate /boot partition. If things work out well, I'm guessing Ubuntu may use btrfs as the default filesystem in another release or three.
- OpenOffice.org is replaced by LibreOffice
- Banshee replaces RhythmBox
- Menu bars show up in the top panel (the global menu bar), so users might get a bit disoriented at times when trying to access menu options.
- Kernel 2.6.38 is being used, but it's got some power management issues so mobile users might want to take that into consideration before upgrading.