I don't need to know anything about it to know that MS's VM works, Sun's doesn't, and I'd rather not have Sun's but I can't use MS's for Mozilla.
I've never seen any problem with MS having their own version, allowing people to use their proprietary functions if they want to, or use pure Java if they want to. Nobody's forcing people to use the proprietary stuff in their code, they use it because they prefer it.
15 to 30% faster is still ass slow compared to Microsoft's VM loading. Apple's can't even be used as a consideration since it only runs on MacOS of a certain version. I'm talking Windows.