I think Konqueror is actually better than Mozilla (and KGet also rulez), however I can only test it with the Apache server I've installed in my own machine
"firefox is not better then IE security wised (has been proven by several hackers, etc). Because its getting more popular, its getting more targetted, and therefor more security holes are detected as well. Since IE is sort of integrated into Windows, this makes it a bit more dangerous i guess, but nevertheless Firefox does not add more security."
If a hole is detected, it will be fixed in 1-2 days even if Netscape has no time to do so (because EVERYONE will be able to do so)
also if I am using Windows 98 and refuse to pay for licensing XP because of its "activition" cr*p and my slow computer, I won't get any security update anymore
about the speed issue: there is actually something like "Quick Launch" option during the Mozilla installation (load Mozilla into the memory during Windows start), not sure about Firefox but you can take a look