It all depends on your expectations. It is marginally slower when navigating menus. And the colors in the menus are not as good. But, when it comes to displaying HDTV, it looks just as good IMHO.
And honestly, I spend more time watching than playing in the menus! I also found the noise of the Xbox 360 far more annoying than slow menus, especially in the bedroom.
1: Dimension 9200 - Vista Ult, 2.4GHz Q6600 Core2Quad, 4GB RAM, 160GB, 750GB, 500GB USB, Nvidia 8300GS, PVR-150, HDTV Wonder, Vbox 3560, X360, DMA2100
2: HP m376n - MCE 2005, 2.6 P4 w/HT, 1GB RAM, 250GB, 400GB USB HD, Nvidia 6200, Emuzed MAUI, X360