This is a gush. I am probably one of the few people in the world really, really excited about MathML fonts!
For those into mathematics in general and MathML in particular, and getting it into e-books and print; a giant leap forward has been taken with the announcement on the 28th May 2010 (a day I was not sure would ever arrive); STIX fonts Ver 1 has been released. We have been using the mysterious, hard to find betas for what seem forever, but birthdays do arrive.
My/our/world's deepest gratitude (I think that is the best word) to the STIX team for completing this Herculean job. 10 years seems a long wait, but now the wait is over. The crowning glory is the MathML using/rendering technology is poised, ready, available and usable to exploit the font work to its fullest.