Konqueror It is far from quick. It has trouble with Bnaking websites (
www.westpac.com.au is a night mare and it works fine in mozilla and Internet Explorer ). It certainly doesn't have the user base that mozilla has.
It's getting better - you don't need the QT library at all to make KHTML work, just like Apple don't use QT in their Safari browser, but you need some GUI library to display the pages 
I never said it did.
Apple wrong about their decision do adopt KHTML instead of Mozilla/Gecko?
I don't use mac so I don't care. Beside, Apple has enough resources to make it work well. Amiga doesn't. Don't get disapointed if they ever do port itand it turns out to be crap.
(I can't really call the XUL think a good GUI, sorry)..............Go do some checking how many apps are based on QT and how many apps are based on Mozilla's XUL engine, then come back 
Again I don't care. I didn't argue anything about QT aside from what it's purpose is. Some one asked and I answered. How about you go look and find out or do what ever it is your on about. :-D
....by porting mozilla - you're porting a browser, and not much more......
Wrong! Mozilla comes with an email and chat client as well. You need to port the Gecko engine which could be used for much more than just a web browser. An email client might use it to deal with HTML content in emails for example. Perhaps you should now go and do some checking :-D
The Gecko engine has come a long way since the early days. It was exceptionally slow to begin with but it has been refinded a lot since then.