You could potentially notice an improvement in the picture coming out of your cable box. Some HDTV's don't do a very good job of presenting 480i signals on a 1080p screen. The 997 will scale all such video to 1080p. Just depends on how well your TV/projector accomplishes this task. My TV is horrible with standard definition.

Don't forget the sound. How are you transporting the sound from your BD & HD-DVD players to your 990? If you're using coax or optical you're not getting the new lossless audio formats Dolby TruHD or DTS Master Audio. The only way to get those to your 990 is through multi-channel analog outputs from the back of your disc players to the 990. The 997 will simplify this by using the HDMI cable to transport the sound signal of the new formats.

I must confess that I cannot give personal testimony to the improvements these new formats provide. My PS3 does not have analog outs. This is why I'm waiting for the 997.

Please forgive the redundancy of my post. I started to write this before KOYAAN posted, but got busy doing something else!