I think you would be happy with the 970 although the Outlaw's 30 day return policy makes it easy to find out. I'm running a 970 in my bedroom using a Sony DVD player for movies and a Linn Ikemi for CD's. The Ikemi is hooked up analog only utilizing single-ended IC's. The sound is very transparent in stereo bypass mode and does not seem to limit the Ikemi in any way. I'll occasionally add DPLII processing to a CD via the Ikemi and it also sounds nice.

If you're using analog outputs from a CD player with good DAC's (or other analog device) the 970 should be transparent enough to reproduce the sound faithfully. If you're coming digital out of a CD player or transport and using the 970's internal DAC's for music the sound is pretty good but the 990 has higher quality internal DAC's (the 990 also upsamples). The 990 is a $1099 processor vs. the 970 costing $699 so higher quality internals are expected.

To simplify:
* 990 & 970 should sound very similar on movies (same processor chip)
* 990 & 970 should sound very similar in analog bypass mode
* Using it's internal DAC's the 990 should be better than a 970 when processing a SPDIF digital signal on PCM sources (CD's, cable radio, etc.)