The 970 probably has comparable DAC's to the 950 and an analog section that is at least equal to the 950, so sonically the improvement is likely to be slim. It has a newer generation DSP chip that offers a few extra features (Pro Logic IIx, AV sync adjustment, an extra crossover adjustment for the surround back speakers, and separate distances settings for all eight speakers). It also offers more advanced video switching (a third component input as well as transcoding of composite and s-video sources to the component output), DVI switching, and a refined version of the 950's analog bass management switch (offering three options: off, HPF/LPF, and digital). The 950 did come with a more powerful remote (the SL-9000 supports learning and limited macros, which the Cat48 lacks) and a second zone.

I don't know what firmware version 970's are presently shipping with, but I doubt that it's the beta (since that version hasn't been officially adopted yet). All indications are that the beta version has made significant improvements on the "no audio" problem.