Block Completion:
Block Completion ensures that code blocks are properly closed. It will automatically close a block (usually with an 'end;') when hitting return after opening a code block.

Code Folding:
The editor can "fold" individual sections of code so that the folded code is hidden from view. (Region folding may not be available.)

SyncEdit:
The SyncEdit feature lets developers simultaneously edit identical identifiers in code. As changes are made to the first identifier, the same change is performed automatically on the other identifiers. Code Writers can also tab to different jump points to navigate to specific identifiers in code.

Editor Line Numbers:
The editor provides line numbering. By default, every tenth line is numbered, as well as the line number for the current line.

Line Change Indicators:
The Gutter shows information about the status of the lines in the editor. Lines changed since the last save are marked with a yellow bar. Lines changed since the file was first opened and before the last save are marked with green.

Guidelines:
The Form Designer now provides guidelines that make spacing and aligning controls a vastly easier task. When controls are properly aligned or spaced, the designer will display a visual guideline that helps "snap" the components into alignment. The graphic below shows the feature in action. (Already available in SCAR, but it's unstable...)

Stability:
The new form designer won't crash every 5 minutes.
New regex support:
This will offer renewed support for regular expressions,
with back-testing.
(Most text and images taken from: http://dn.codegear.com/article/34323, some features may differ slightly from the images)