OMEMO's cryptographic security has already been audited as well: https://conversations.im/omemo/audit.pdf . I should know as we (Pacific Research Alliance) funded the audit of OMEMO ;) . Auditing merely the protocol seems a little problematic, it's quite rare for vulnerabilities to be in an encryption protocol itself and much more common for it to be in the implementation. There doesn't seem to be any application which actually implements this library right now, let alone a network capable of supporting it. In OMEMO's case we also audited the OMEMO implementation in Conversations where it was originally conceived.
The only difference I can tell from their website is "Room consistency: Group chat participants are confident that they are in the same room". This seems like a pretty niche area to be concerned about, and in practice can be solved by a properly secured network. Although I am no cryptographer I believe OMEMO may offer the same quality as well, because all the messages must be encrypted for each participant, so at worst you could fake an identical room with identical participants, which doesn't really seem like a valid security problem.
While I love to see new research and further development into this area, it seems this is a little late to the party.