Actually it's not, not if you spend 20 minutes sorting it out.
I edited the registry to turn off the UAC permanently and also the auto defrag and a few other bits and bobs and its fine now, none of the usual complaints are valid. It's only running 0.8gb of RAM at idle.
Anyone that can't afford to get W7 read this:
http://www.tweakguides.com/VA_1.html