I really like it and am using it all the time now. Since it's based on Gecko (Firefox 1.5) it has all the excellent functionality of Firefox plus a lot of neat features. The thing I like the best is it loads pages very quickly, even when there is stuff running in the background.
It doesn't have the ability to use Firefox extensions as of yet, but from the comments in the forums I wouldn't be surprised if that is added before the release version.