Does anyone here use it while watching movies?

I have heard other "theater compensations", (THX processing to be specific) that have "deadened" the sound and reduced the amount of audio detail and clarity. How does the 990's theater compensation affect the level of detail?

Never used it; never will. In my system, the 990 does a fantastic job with normal settings.

All theater compensation follows the same basic formula, be it THX or otherwise, and that is to filter out some of the high frequency. In cases where the mix was intended for a movie theater and the highs were overblown, theater compensation can help remove alleviate harshness. In other cases, it weakens teh ihgh end - creating the "deadened" sound you've experienced. Personally, I don't use theater compensation normally, so I can't speak to how the 990's theater comp compares.

I used theater compensation quite frequently with the 950. I have had no need of it with the 990.

never used it, filters = bad

I always wondered what the specs were on the theater compensation filter. I wonder at what frequency the rolloff starts and its slope.