I wouldn't expect the 970 to offer a sonic upgrade (if there was one, it
should be subtle, since I'd expect both companies to get the analog section design pretty well right and the DAC being used is almost identical). The 1070 will of course sound the same (same platform as the 970 but with amps under the hood), but it could be a temporary solution until the summer. The 1070/970 (and the 990) would also let you apply Pro Logic II properly, which isn't possible with your non-updated LMC. I wrote a summary of the situation with the original LMC-1 firmware on an old thread, which cburbs added to his
beta notes under "LMC processing options" - I'll quote the relevant part.
Here's where it gets a bit curious, though. In the LMC-1, PLIIx can only be applied to analog or PCM stereo sources, at which point it will produce an output that is 5.1, 6.1, or 7.1 (depending on how many speakers your system has). It cannot be overlayed onto a Dolby Digital or DTS bitstream, although according to Dolby's description of the format it is intended to support at least Dolby Digital bitstreams. I've also seen a number of PLIIx implementations that also support being overlayed onto DTS bitstreams (the processing is simply applied after the DTS bitstream is decoded). This means that if you have a Dolby 2.0 source (many cable or satellite broadcasts or older TV shows and movies on DVD), you won't be able to apply surround processing for the digital audio input. The current solution is to toggle to a stereo analog connection for that input, which does allow Pro Logic IIx processing (although it means you are now relying on the source component's DAC, then the LMC-1's ADC, and finally the LMC-1's DAC). You may also be able to set your cable or satellite box to output PCM instead of a bitstream - the only drawback there being that you'd lose access to any Dolby Digital 5.1 material on broadcasts that include it (it would be downmixed to stereo). DVD players also allow this, but once again it means losing access to Dolby Digital 5.1 when you use discs that do include it.
The updated firmware fixes this (allowing you to apply Pro Logic II processing to Dolby 2.0 sources), but it does so by "breaking" the triple crossover bass management and instead applying a single crossover to all channels.
You can't
exactly send the same signal (left/right) to rears to simulate an A/B switch with the 990, but you
do have a 5 stereo or 7 Stereo mode (left is copied to left surround and even left back surround if there is one, same for right, and the center gets a summed signal). There's also a second zone similar to what the LMC-1 has, with the ability to switch video added to the mix.
Addressable inputs are handy because it doesn't lock you into only using coaxial for a certain input's digital audio connection, or for having one source (DVD player) act as two inputs (one for DVD viewing and another for stereo CD listening).
The analog video transcoding is sometimes mis-labeled "upconverting." Composite and s-video inputs are output at 480i through the component input, just as the LMC-1 does. "Upconverting" really would only apply if those sources are also converted to 480p or a higher resolution along the way, which neither the 990 nor the LMC-1 do.
The LMC-1 does
not have stereo analog bypass. The
only way to send an analog signal all the way through the LMC-1 without undergoing an analog-to-digital conversion and a subsequent digital-to-analog conversion is the 7.1 Direct input. The mode labeled "bypass" on the LMC-1 really should be called simply "stereo" because it
doesn't bypass the digital processing.