At a glance, it seems that this is just a technology that's build on top of ASP.NET, so surely it's got all the goodness of ASP.NET + more build-in goodness.
Actually, I'd almost say it's the opposite.
It's got all the goodness of ASP.NET locked away where you can't easily use to customize your solution.
So if you are after something out of the box with light modifications, Sharepoint is really your friend.
As soon as you want heavy modifications, it feels like a complete road block.
Still, it has some really great publishing features, which distinctively makes it very compelling for an enterprise to use and set up.
I'll have more to say very soon.