A lot depends on how your display interprets the signals.
On my Aquos panel, the component is ovescanned so I don't see the whole image, so I use HDMI.
On some combinations, HDMI takes a little time to handshake so you go without picture for a bit each time you change channels. In those cases you might prefer component.
Also, scaling and deinterlacing can be a factor. One receiver/set combo may work great for HDMI with 1920x1080i, but may not be optimal upscaling from 480i for instance.