Actually, Adobe is a big part of this, and Bill McCoy has expressed his enthusiasm of the new zip-based container spec. I haven't seen the Sony name, but despite their history I wouldn't give up on them completely and for all time.
DRM has not been addressed yet, so each company has freedom to add that as they see fit. That also means that interoperability at the consumer level can still be out of reach at the moment for DRM'd material. But based on my limited understand so far, it seems that this is a huge step forward, both because industry leaders are working together, and because developments like this would appear to be a prerequisite for any hope of a good interoperable DRM solution.