Stephen Schultz at Associated Content is very happy with Ubuntu and Beryl compared to Vista
Read about it here
In comparing this to Windows Vista, I should mention, this upgrade required no new computer hardware. Granted, I already had a pretty good graphics card (ATI 800Radeon). But the addition of Beryl did not drain my system significantly as many of the graphic effects will do with Vista. And, if I so choose to add further effects to Beryl it tells me which adds more power drag and what doesn't.