This is no lightweight freeware project, this is production proven, high end animation software which has an impressive list of credits spanning two decades (things like ‘The Tale of the Princess Kaguya’, ‘Howl’s Moving Castle’, ‘Ponyo’, ‘The Wind Rises’, ‘Phantom Boy’,’Anastassia’, & ‘Futurama’). 
The deal that sees the software becoming open source means that the developers can try to make it the industry standard and will offer customised premium options for clients wanting to take on large projects.

Cartoon Brew have a good rundown of the history of the software so check it out here.

Here is the link to the open source homepage where you can get more info and the download.