I'm in beta, too. The NDA has lifted a bit, you are allowed to talk but can't post screenshots or videos.
The game is awesome, especially if you love DotA, you will love Heroes of Newerth The Linux port is great, it has 64-bit support, multicore support, RandR support and a lot more. The graphics are fantastic, definitly one of the best looking games for Linux.
Well they have their 10,000 fans on Facebook and will be sending out the invites in about 12 hours time. They stated that if you become a fan before the invites get sent out, you will still get an invite.
I've been playing this pretty much since Julius invited me (thanks again!) and also invited some friends in. I didn't play DotA much but enough to realize that this game is in many aspects very much identical. That's not a bad thing though, it's a great game.
But I guess it'll be very hard to get into for someone who never played DotA.