If you want to discuss about KDE4 speed and resource needs... discuss about those. Do not talk about Operating Systems if you do not understand that Linux (the monolith kernel) is the Operating System and not just a kernel. Same thing does not apply to Microkernel.
KDE4 is fast, powerfull and still lacks some important features. But it is just in the beging of the big porting. KDE 3 was not great and best either when 3.0 - 3.1 was released. After 3.2 it started to develop to be better and until 3.4 hit the road, it was got that what was waited from it. Now let KDE4 develop and do not bash it down for political misbelieveing and fanboyism...!