Overall I am happy with the New Firefox, Having to go back to FF3.6 when I swapped over to ubuntu last week, after having used all the FF4 betas and FF4 rc1, brought it home to me how good FF4 was and I was relieved when I received the automatic upgrade.
I must admit I was dubious about loosing my Menu Bar but I find the drop down way of accessing my menu items is quite good to use and the extra space it frees up is worth having.
One of the things with FF4 that has irritated me was the new look of the Add-ons, it seemed to be so spread out and, even with my font size reduced, I had to scroll to get to my add-ons. OK I know I'm lazy but I do like to have what I am working on all showing on the screen at the same time.
Having a bit of rummage around the net I came across a report on the
Slim Add-on Manager on the
ghacks site. In use it certainly makes the lists a lot more compact.