IBrowse 2.4 rocks perfectly for me - almost.
@djnick - set the fonts! It's worth it!
Otherwise - install was easy as pie. My only complaint - at work we use MS Exchang & OWA. With IBrowse 2.3 I could login in from home. Since I updated to 2.4, OWA keeps complaining that I need java enabled, which I've set all ways to heaven, even via URL prefs, but it still fails. Unfortunately, I can't get AMISSL 2.2 to install properly so that I can go back to IB 2.3 to see what I might be missing.
Other than that, I definitely see a speed improvement.
Edit - I do not think it is IBrowse that fails the Javascript - I can't get IBrowse 2.3 to connect now. I can only surmise that the new MUI clasees are interfering with the Javascript processing.

Now I have to use windoze to connect to the work email - yuck!