As Windows Vista Beta 1 released, the word-war started whether Microsoft has copied Apple's Tiger techonologies or not. Some say that Microsoft has copied, they give examples of similarity in icons, presentation system approach, and icon naming, and some say that Microsoft has not copied but improved, they quote the examples of features like virtual folders, network presentation and search as you type.
Eweek has done a comparision of both operating systems and result came out in form of a very detailed and useful article.
When Windows Vista ships in late 2006, Windows will mimic many features of Apple's Tiger and go beyond it. But while Microsoft introduces the world to Vista, Apple is keeping mum about its next version of Mac OS X, which Steve Jobs has said will ship at about the same time as Vista. It is the Intel-ready Leopard, not Tiger, that will be Apple's answer to Windows Vista.
For details please check the link provided.