Yeah but how many *brand new* XP machines did you buy that ran like crap? I suspect the answer is "none" because Microsoft's recommendations to hardware manufacturers were realistic (128 meg recommended). Now compare that to Vista:
My brother bought himself a brand-new Vista machine, with 512 meg of RAM, and it's as slow as a snail through molasses. Microsoft gave the hardware manufacturers bad advice when they said 512 meg was enough space.
128 Meg for XP actually does run like crap. I have an old machine with 256 Meg of ram that keeps resorting to the swap file every time I have moer than one app open at a time. The fact is every operating system has had the same critisisms of bloatware, power hungry, bad compatibility etc. Then after a few years, everyone forgets how much they used to hate it. Vista may have been a little worse than normal but it does always happen.
Our OS who art in CPU, UNIX be thy name. Thy programs run, thy syscalls done, In kernel as it is in user!