The flexibility it provides to the users is great. Features like Auto complete, Debug, Build, Clean, provision to attach Valgrind etc..are mind blowing.
It sticks on to the same standard shortcuts for compile, build, auto complete etc which most of the other applications use.
QML support and other supports it provides are very much appreciable.
Excellent for cross platform app development.
Qt Designer- The best application user interface with the integrated editor.
Makes a user Build, run, and deploy Qt projects that target multiple desktop and mobile platforms, such as Microsoft Windows, Mac OS X, Linux, Android, BlackBerry 10, embedded Linux, iOS, and QNX
Great that Python, Ruby, Java bindings can be used to this.
Occasional Crashing and freezing disrupts its name a little. It could be great if there was a provision to integrate other text editors to it so that developers who have expertise in other editors could easily use the same.
Qt is growing very big so it is hard to learn it without external help. Fortunately once you get the hang of things, all becomes much easier
Destroying developers skill to do things: CPP developers are forced to think the Qt way rather than proper CPP way to do the development. In fact ruining a CPP developers skill on pure CPP application development.
Issues with installing database drivers.
Very Heavy: requires vast memory for compilation
Single Threaded: ui updations can only be handled from a single thread which really makes it hard to develop multi threaded applications effectively.
QMake is outdated (and complicated for more advanced projects) and everyone knows that. Trolls are looking for a better build tool even now.
Developing embedded Linux applications as well as windows desktop applications.
Cross platform development capability is the main thing I like about it.