As an update, I did purchase the 975. Between it, my PS3, and Netflix, running with a stereo speaker set up was... less than intuitive.

I was hopeful that the firmware update would resolve some of the problems because some of the fixes described were similar to my experience:

-LFE/Subwoofer management issues related to specific formats has been corrected
Often my LFM-1 just didn't seem to be receiving any signal, and there seemed to be discrepancy between the built in 975 LF test signal and the levels from sound or music sources. Setting it by ear is iffy, I know.

-An issue with inconsistent volume levels between surround modes has been corrected
From a PS3/Netflix 5.1 source, output levels were very low. If available I would toggle to the stereo output in Netflix and levels returned to reasonable.

-Issues with incorrect front panel display icons have been corrected
As input streams change format, my speaker configuration display on the 975 changes, sometimes omitting the sub.

It turned out that my 975 shipped with the 5.3 firmware, so none of this has been resolved. I know my observations and this description is not exhaustive enough for thorough troubleshooting, but I never made the time to really analyze what was happening. I could get it 'good enough' for the little time I've spent watching.

After considering some local used Adcom and Rotel multi-channel amps, today I ordered one of the refurb 7075 amps via Outlaw's eBay sales. ($500 shipped, 5 year warranty, still one left.) I'll probably get out the drill and fish tape this weekend and install some wiring and panels. I'm hopeful my 5.1 speaker rig will smooth some of these behaviors.

I'm most looking forward to experiencing LCD Soundsystem's "Shut Up And Play The Hits" as it was mixed in 5.1. I've still only watched it in stereo.