How well JUCE performs when compared to toolkits like FLTK and Nana? Is there any chart comparing them?
It's a hard enough problem to devise meaningful performance tests for a UI framework, since the things that people use them for in the real world varies so enormously. So the idea of finding a test that you could somehow implement in multiple toolkits and get any kind of useful metrics from is beyond anything I can think of!
You could probably dig out a few vaguely equivalent core classes from these frameworks and bodge together some sort of test for them, but I doubt if it would teach you anything that would reliably indicate their suitability for whatever actual app that you have in mind.
Performance is important to us though - we're always keen to hear of any performance snags that you hit in real-world code!