I tried it yesterday. I liked a lot about it but I did have some issues. The two biggies that were deal breakers for me were that as ironic as it was, there was no google toolbar and I use that all the time in firefox. Another issues I had was it would scroll down but not up using the mouse pad on my keyboard.
Ill give it another try when it is out of Beta though and see how it is. It shows some good promise!