From the release notes:
"ReactOS now has the infrastructure needed to theme the user interface and shell, allowing users to install and use something besides the classic Windows theme."
Another thing noted on the homepage to keep in mind -- "Please bear in mind that ReactOS 0.3.14 is still in alpha stage, meaning it is not feature-complete and is not recommended for everyday use."
That being said, I gave it another shot in VirtualBox with the recommended guest settings (Windows NT 4) and I was pleasantly surprised of how smooth it felt. This project has come a long way.
