I've used a couple DVI sources (Pace Micro HD cable box and OPPO Digital 971H ) and several HDMI sources (Scientific Atlanta 8300HD cable box/DVR, three different OPPO DVD players , Toshiba HD-A2 , Panasonic BD30 , and OPPO BDP-83 ) with the 990's DVI switching. Both DVI and HDMI connections work in the same way: the 990 provides switching for more than one source to connect to a single DVI or HDMI input on a TV. I've even put a separate HDMI switch in front of one of the 990's DVI ports. Since the 990's DVI switching is video only (as is the case with the HDMI switching on some receivers, even today), you add in an audio connection and you're all set.

DVI and HDMI are digital video formats. Component is analog. DVD, Blu-ray, and HD broadcasts are all digital video formats. Most HDTV's (with the obvious exception of the CRT that is now rarely found) use digital display technologies. Keeping a video signal digital from source to screen is better. There are some other benefits. DVI/HDMI can handle 1080p, while most implementations of component stop at 1080i (component is capable of 1080p, but finding a component 1080p source is difficult as is finding a display that will accept 1080p via component). Some DVD players offer really good video processing (scaling and deinterlacing) - potentially better than the TV they end up connected to - but copy protection fears prevent those player manufacturers from allowing component video output at resolutions above 480p (no 720p or 1080i) when watching CSS-encrypted DVD's. Since nearly all commercial DVD releases use CSS, that means a good scaling DVD player can only scale at the HDMI output. Lastly, there is a "feature" in the Blu-ray specs that has not yet been used on any discs: the Image Constraint Token (or ICT). The ICT can be enabled on a disc, at which point the Blu-ray player must downscale the video to 540p for the component output. Using the HDMI output with a Blu-ray player means that you never have to worry about some studio down the road deciding to do unpleasant things to their customer base and start turning ICT on for new releases.