You can read about the bugs in that part of the forum but I haven’t found any issues pertaining to me.
You can’t save a project in the beta and open it in the earlier version - it’s not backward compatible that way but you can copy/paste or drag stuff between versions.
Honestly, download the RC and install to a different folder so it doesn’t overwrite your older version and play around/explore both until it answers your question.
It’s here just waiting for you 
[url]Scrivener 3.0 Beta - Release Candidate 10 (Download Links & Change List)]