I've been using using Linux with GUIs for about four years now. Many of the e2 nodes dealing with GNU/Linux in general that I've seen are from several years ago, whining about technology that has evolved dramatically in the past few years (and indeed, the same arguments exist still outside of e2). Here's one that's more recent, however.
Interestingly, the competing toolkit problem looks to be one that too will soon be overcome. But in the past three days, the KDE people have announced the QtGTK library which integrates the Qt and Glib event loops (the dialogs, DCOP, etc.); the GTK-Qt Theme Engine, which is a GTK theme that acts as a connectivity layer to Qt, making GTK apps mimic the look of Qt ones; and the OpenOffice.org KDE Native Widget Framework, which will integrate Qt settings into OpenOffice.org.
Of course, this is all initial-release alpha stuff right now, and I wouldn't recommend casual users even try to get the aforementioned software running on their boxen--I certainly won't just yet. Still, given the pace at which I've seen Free/Open Source Software develop over the years, hopefully they'll be release-ready soon.
Update: lj (who is doubtless more technically savvy than I am) says: Something to consider about wrapping GTK into QT is that the two toolkits are unlikely to be 100% compatible in behaviour - with Java/AWT, it was supposed to be possible to create an application that behaved like whatever operating it was being run on, but what you actually ended up with was an application that behaved like a Java application, and looked superficially similar to the OS it was running on (for example, running on Windows with Windows widgets, but no file menu).
(In my opinion), unless the two toolkits can agree on how applications should behave as well as look, there will always be incosistencies when apps from each toolkit are used side-by-side.
My reply: I may very well be way off-base here, but I believe this is what the QtGTK library is supposed to accomplish: "This makes it possible to freely use KDE dialogs, DCOP, KDE IO and other KDE technology in any GTK+ application just like they would be native." (see QtGTK article below)
- KDE.OpenOffice.org: Native Widget Framework Available (8 Jan 2004): http://dot.kde.org/1073557624/
- GTK-Qt Theme Engine Does Cross-Desktop Styling (8 Jan 2004): http://dot.kde.org/1073599985/
- QtGTK: GTK+ Apps Get Free Reign on KDE Technology (9 Jan 2004): http://dot.kde.org/1073668213/
- /.: GNOME/KDE Integration Gets A Few Boosts (9 Jan 2004): http://developers.slashdot.org/article.pl?sid=04/01/10/1750257