very good artical to read too. you might want to check it out.
yes i have noticed that some programs like OO (open office) and Opera can take longer to open in a heavy GUI, but then i also run it on questionable hardware that is not 100% linux compatable. heck its not even 100% compatable with windows for that matter.
i have also noticed that once i have the programs up and running they are far more stable then under windows, and run faster once they are fired up. but the best thing is when my GUI locks up (and it will from time to time, but no were near as often as my much beefier windows box that is 100% complient hardware) all i need to do is reset the GUI, and not my entire system. my uptime currently on my RH9 box is over 50 days and ive only had to reset my GUI 2 times. that only due to the fact i left Opera open for about 3 weeks straight. everything worked for the most part, but i lost access to seeing the hotkeys added to my desktop, and i lost access to viewing my home dir in the GUI. all of the CLI still worked, gAIM, Y!, Opera, OO, and XMMS all worked perfectly for me.
30sec after resetting the GUI i was back in and all worked just fine.