Have downloaded it this morning and converted a catalaog of some 20,000 images to play with. Looks rather stable so far, but it is too early to comment on that aspect yet.
The new features were known for a while, no surprises. The UI is imroved here and there. Feels good.
Cheers.
PS: Peachpit press will provide a LR version 1.1 pdf file as an addendum to the Martin Evening's LR book. One can register on their web site using the ISBN code of the book and download it free of charge when it becomes available.