I remember being turned off by the use of a preprocessor. Is that still required?

Only if you use their (very nice) event/property system. If you don't inherit from QObject then you generally don't need the preprocessor.

That said, QMake and CMake both deal with the preprocessor for you.

By the way, it's a code generator, not a preprocessor. Everything you write is valid C++, it's just that there is additional code being generated that interfaces with your code.