The download went fine but launching the game was muuuuuch slower than usual. Also, the pop up window that informs you about being a "test" player for the new launcher has a hyperlink on "if you want more information click here", which takes you to this thread where no specific info is given about what the differences are.
Thanks for working on improvements, but it's definitely not nice to be put on a test version without opt-in / opt-out choice, without any information to check about what the changes are and in my case making the experience worse, sadly.