I don't like the default font in FF, or the fact that it renders most sites at double what IE does, and alot of extra forum controls work or don't depending on the phase of the moon.
But since I often surf while in linux..... whats not to love?
Firefox memory leak fix
Not sure if this will help, but saying as how this pertains to the Firefox memory leak, might as well give it a try. Found it on a couple sites:
1. Open Firefox and go to the Address Bar. Type in about:config and then press Enter.
2. Right Click in the page and select New -> Boolean.
3. In the box that pops up enter config.trim_on_minimize. Press Enter.
4. Now select True and then press Enter.
5. Restart Firefox.
Grabbed the article from HERE
"This little fix will move Firefox to your hard drive when you minimize it, and as a result it will take up less than 10MB of memory while minimized. So far, from my experiences with using this today, when you maximize Firefox it will obviously increase the memory usage. However, it does not seem to go back up to the insane amount that it was at before minimizing it. For example, Firefox was at 180MB of memory usage and then I minimized it and after a few seconds I maximized it. After maximizing it and continuing on my routine business it appeared to only have gone up to 60MB."