Files 354 first sights
 Nautilus menu moved into a single button on top right, similar as Firefox! Also we have the symbolic icons on the left, which seems pretty. This is the new Adwaita theme with minor changes.
 Window menu while looks good when is closed but it feels a bit messy if you open it. This is something that Unity tried to solve with HUD and Gnome also needs a solution there.
 Right click on file misses some options, but this is I guess because of my compile..
 Same applies for right-clicking on Nautilus content
 Compact view is removed so we have Icon and List view only.
 Also the extra panel has been removed but Tabs are still here, with some CSS bugs :)
 The location bar which open with “Ctrl+l”
 And this is my favorite new feature! A new real time search. It looks and display files as you’re typing, similar to Ajax search in webpages. Of course if your looking inside of thousands of files you have to wait a bit.
 And this is the help
First off, this isn’t a complete software. So we must way till version 3.90 that UI changes will be final. But so far Nautilus feels much more modern than 340. And if it needs one or two more clicks for an non-usual action, it doesn’t really matter. Sometimes a nice appearance is more important than having things practical.
Major changes in 3.5.4
+* Add Copy To and Move To actions
+* Add a notification while ejecting volumes
+* List view:
+ – New date format display
+ – Use a list model instead of a tree model for list view
+ – Use a better default column order
+ – Change some list column names
+ – Use 32px icons by default
+ – Tweak padding
+ – “Just type” search
+ – Combine the search bar and the query editor
+ – Tracker engine performance improvements and fixes
+ – Add a recent files place
+ – Use symbolic icons
+ – Improve order of the items
+ – Change toolbar layout to the GNOME 3 style
+ – Don’t show titlebar when maximized
+ – Use a linked style for the pathbar
+ – Migrate the menubar to a gear menu
+ – Remove “Go” menu
+ – Remove “Bookmarks” menu
+* Remove “Text beside icons” option for icon view
+* Fix loading string not disappearing in image properties on load
Update (20/7): There have been some large discussions about the removal of Nautilus Compact View; you can read here: https://mail.gnome.org/archives/nautilus-list/2012-July/thread.html