I tend avoid apps that are implemented in cross-platform frameworks for simple quality reasons. Native apps tend to be of higher quality (depending on the engineer who wrote them, of course). Cross-platform frameworks tend to be "least common denominator" kinds of things.
Is it better to require most computer users to purchase, maintain, and carry multiple brands of computer in order to run exclusive applications, each designed for a different brand of computer?
Which widget set is "native" on X11/Linux? Is it GTK+, Qt, or something else? Because both of those are ported to Windows, what makes them any more "native" on X11/Linux than on Windows?