I like how they called it "Lumberyard"--because lumberyards have such a positive association with the Amazon.
Then again, they also named their book reader after the best way to burn books.
Now, on a more serious note, the engine itself caught my eye a while ago. It's nice to see a new competitor in a domain with such overarching powers as Unity and Unreal. This engine is the result Amazon pouring a ridiculous amount of money into buying CryEngine rights, so Lumberyard is basically a free CryEngine. Who knew we would get a free CryEngine?
Personaly, I think the AWS integration looks kind of amazing, because it is supposed to handle netcode woes. Netcode woes are terrible, I would not wish them on my worst enemy.
I wonder what other magic Amazon baked in there?
My one complaint is that even though it is free, the engine is more restricted than Unity or Unreal--so we'll have to see if that affects its adoption.