Paul Thurrott compares Tiger to Windows Vista Beta 1
... which is quite obviously not a really good comparison, since Microsoft is far from being done with Vista, which will be released at the very end of 2006, at a time, when Leopard will be released (Mac OS X 10.5) - of which we basically know nothing other than that it will be released then and that it'll support both PowerPC and intel based Macs.
Paul Thurrott doesn't seem to want to let go of his idea that Tiger has copied some features from Microsoft's plans for Vista, but he defends himself a little bit. Maybe in his next big review, he'll finally agree that Spotlight has been released and was planned ever since Copland (1995), whereas WinFS was "announced" in 2003 but will not ship until sometime in 2007 - and that claiming it was somehow Microsoft's idea and Apple was "copying early" does
sound a bit strange for someone who was there when Apple first announced plans for this type of desktop search.
Either way: You can read Thurrott's comparison
if you want to. ;)