Differences from the 499 to the 500 or the 501

Actually im curious about why on the main page the last version shown its the 499 and in the download page u get the 500 and can upgrade to 501...only have found 2 difernces so far:

1) theres a dva broadband option

2) cant play movies in overlay mode 1 (at least in my comp).

Any one cares to explain?