I'd love the newer version of Safari but I'm running Jaguar...one OS below the minimum requirements. The version I have now hangs up quite a bit, a problem I don't have with other browsers.
Firefox works great on our school computers, but I don't suppose I have ever tried Java there. I use Mozilla Suite here on Linux, with no Java. I just don't encounter the need to use it. I think Mozilla is great, but I use IE on Windows and on my old Macs. I just use what works for me, so yes as said by others you won't find the perfect browser. It also depends on what you do. If it works, use it.
I decided to give Firefox another try and I'm VERY glad I did. This is coming from a former Safari die-hard. I downloaded the newest Release Candidate of Firefox 1.5 and it's great. As far as I can tell, it fixed all of my complaints with Firefox (middle button on Mighty Mouse no longer activates back and forward when you try to side-scroll, etc.) It's way snappier than any other version of Firefox I've used and seems to be very stable. I've only been using it one day, though, so far, but I really love it.
EDIT: It also doesn't seem to leak as much memory as Safari.