And then you'll have a bad copy of a bad copy.

The fit and finish of linux desktops, especially KDE, are nowhere near as good as the Mac, and adding a theme which kind of sort of makes it look like OS X only serves to highlight where it doesn't match up.

As a long time Mac user and now Linux user the only desktop which is vaguely tolerable is Elementary OS as at least someone there with a good eye for detail went through and made sure it all fits together.

Why? Every time KDE (or even GNOME) undergoes major changes, so many tweaks are also broken. One of the reasons the OS X UI/Ux is so consistent and reliable and mature is because its developers aren't saying "f it, start over" every few years.

And there are bugs and annoying aspects to Aqua, it's not perfect, but it is stable.

Try to run Pages, iTunes, XCode or Apple Script on KDE.