I would also like to jump on the Juce appreciation band wagon. I’ve been using it for almost three years (as a study tool to begin with, more seriously recently) and can’t say how much I enjoy using it and how much it has taught me. I’ve only recently started to look at other libraries for features that Juce currently doesn’t offer and there is simply no comparison in the wealth of documentation, examples and support.
I would also like to say how useful a tool the Introjucer is. It makes setting up and building an application not only portable but incredibly quick, literally minutes from the download to a working blank application, if only other libraries were this quick and intuitive to set up. I also love the naming system, with autocomplete you really only have to guess at function names, if it makes gramatical sense its probably right, none of this silly underscore abbreviated nonsense, tell me what a function is doing.