>>4
Please don't call it the Win32 API, that name is obsolete. Ever since Vista, when 64-bit went mainstream on Windows, it's been known simply as the Windows API or WinAPI for short.
And yes, there are deprecated functions and other cruft, but it does maintain binary compatibility reaching back nearly 20 years, which is a feet to be commended. On Linux, you're lucky to get binary compatibility beyond 4 years, but that's usually not a problem if you have the source code.
The biggest thing I hate about the Windows API is the overuse of hungarian notation, but fortunately, their newer COM-based APIs like DirectX 11, Direct2D, etc. have cut out as much hungarian as is possible.
Comparing code that uses Windows API versus POSIX layers, I find I have to write around the same amount of code as each to accomplish various tasks.
The biggest thing I hate about Windows development are their dynamic link libraries, and the shit you have to jump through to get SxS support working, export C++ interfaces, make sure you using the correct import libraries, etc. It's a real nightmare compared to ELF shared libraries on Linux/*BSD.