>>10
wxWidgets looks nice
It is not.
- It's practically undocumented (don't point me at their doxygen crap unless you have used it in a large project and found it helpful; I for sure found it completely useless).
- It claims to use native widgets, but it often uses them in strange ways and alters their default behaviour so that your programs won't look or feel native on any platform.
- It suffers from tons of bad design decisions made in its early days, which practically forces you to write a wrapper to shield your code from its suckiness. They should've completely rewritten it years ago.
- It fails to fullfill the #1 requisite of cross-platform GUI toolkits: being cross-platform. You have to actively look out for platform-specific functionality, which is only spastically pointed out in their documentation.