After starting Office 2003 installer, at the product key typing stage, the product key entry field is larger in ReactOS than in Windows 2003 by width and height. The difference is visible on comparison images:
Beside that, there are two bugs with this field:
1) In w2k3, the dashes between parts of the field are visible, in ros they are not visible;
2) When typing product key, in w2k3, typing and removing the symbols works correctly for all parts of the field. In ros, only typing the symbols works correctly. Removing them works only in each part separately, but not in all parts toeghter. See ros-key-field.mp4, w2k3-key-field.mp4 and typing-product-key.log.