I was a long time user of Netscape (since version 1.22...got to be an official beta tester for version 4.0, still have 4.0 Gold edition in a sealed box), but I finally started using IE several months ago because Netscape 4.08 (the last stable version of netscape) was having more and more difficulty with various sites that IE could display just fine, and Netscape 6.x was just too slow and had too many memory leaks.
Mozilla wasn't much better either. I am finally happy to report that Mozilla 0.9.6 is sweet, fast, not too memory hungry, highly compatible, and stable to boot! Netscape 6.2 is sadly a bit behind, and not stable or memory friendly enough for me to use.
One of my big complaints was that Netscape and mozilla both opened new browser windows extremely slowly. This is no longer the case, opening a new window is nice and speedy. AND in 0.9.6 you can actually open links in a new tab in the same window, to save on memory use and make it even speedier. This is great for someone like me who is constantly opening links in a new window.