I've been dealing with the developer on the Reaper forum (via PM). In my testing I've helped him discover 2 bugs in his ProjectConverter which he fixed an posted opnline in less that 30 minutes. He discovered one bug in the Bitwig opening a DAWproject from his export of a Reaper song and reported it to the Bitwig development team.
I've also reported to him a bug in my Studio One export to DAWProject when using his ProjectConverter to bring it into Reaper. Buses were missing and settings of UAD Distresser were all set to a default state, not what the Studio One song had.
On the Reaper forum some have jumped on the feature request to include DAWProject.
I'm assuming one he gets the buses and Distresser settings worked out I would be able to take any older CbB projects into Reaper via aslow3's ReaCWP tool, then export from Reaper into DAWproject via Project Converter and then open it in Studio One and have a reasonable starting point to re-mix if I desired. The sad point is that I cannot do the reverse if/since the new SONAR may not have DAWproject imbedded.