Those keyboards are common for other tablets though, my parents have one that's built into a case for their silly ipad. Built in is great, don't get me wrong but it's not a crazy innovation that people are going to be lining up outside stores to get.
The real question is whether Microsoft is going to outspend Apple or not. That's the only way they've really succeeded in a market in the past decade. The Xbox and Xbox 360 were largely failures on their own merits, Microsoft simply kept dumping cash into them until they had finally gotten where they wanted to go. They need to be prepared to do that again if they want to take on Apple and Google to a lesser extent. There's also this weird cross competition between this, Ultrabooks, OEM Android offerings and so on. Sure they are considered distinct markets by the manufacturers and vendors but I think there is a lot of overlap when it comes to consumer perception and spending.
I expected them to do something original and instead it's just yet another tablet, a bit disappointing.