Does it matter to you if an app is created using Gtk, Qt, or another graphical tool kit? I just published a poll asking what desktop environment you use and to answer that question. I frequently see posters on various forums declining to use a program because it uses a different tool kit than their desktop. How widespread is this behavior and why the preference?
It seems to me that limiting ourselves in this way only lengthens how far applications need to come in order to meet every user's needs. KDE, GNOME, and other environments have been working to ensure interoperability between them, but if our (the users) biases defeat it, then there is still more work to be done.
Please feel free to leave your comments in addition to your vote. If we can identify the reasons for toolkit preference maybe we can help separate the myth from reality and come closer to making GNU/Linux easier and better.