Calendars: Filters and More Colors
You can filter Project-based smart Calendars. Regular filters or Custom Field filters, take your pick.
And, a personal favorite, there are now more color options for Calendars.
Subtasks to Tasks (and vice-versa)
From the table portion of the Gantt Chart you can now move a task further in to or out of the task hierarchy (tasks and subtasks). Major bonus: there are keyboard shortcuts available for these actions.
More Clarity for Audit Reports
Audit Log Reports for comments now show the comment's author so it's easier to see who edited what.
Folder + Project Facelift
The Folder/Project header looks a little different: new font, new Folder/Project icon, and (also new) the icon stays in the same place in the header as you switch between Folder/Project views.
Greyed Out Task Description
Imagine this: two people are editing a long task description at the same time. Before: the task description became greyed out for one person. Now: the task description should work for both people.