For many years it was not possible to attach arbitrary fonts for web pages so that they look identical in the leading browsers. Instead, you had to use images.
Then it was time Cufon library where everything was beautifully rendered. Everything, but not everywhere. In IE visible ugly gap (about half a second) when loading the page, but managed to find a solution.
To avoid this ugly effect, you must:
1. Right afterhide swapped elements
2. just before run cufon
3. show swapped elements