Excellent advice, but as a professional engineer with work lined up all the way into next year, I do need to start making decisions now before I start the next project. As much as I've hated older versions of Protools and swore I'd never use it as my main DAW (I own PT9), the PT12 features look very promising - especially the more geeky stuff like exporting and routing options. Quite an adventure of discovery we were all thrown into to suddenly! :O)

Thedoccal
That article brought tears to my eyes.
 
Then he said this:
Exporting SONAR Projects as OMF Files for Use in Other Applications
https://www.cakewalk.com/Support/Knowledge-Base/2007013040/Exporting-SONAR-Projects-as-OMF-Files-for-Use-in-Other-Applications
 
I will never say a bad thing about ProTools ever again.  Thanks Pro Tools!
 
Edit: Studio One does NOT support the OMF format.  Never mind.

OMF is an ancient format with major limitations...it was good in its time, but check out the knowledgebase article in depth. IMHO SONAR's export functions work much better for transferring projects to other DAWs. That will be the subject of a future Sound on Sound column.
 
Also note that if both programs are open, you can drag and drop files from SONAR to Studio One Pro, as long as they're actual WAV files and not Groove Clips.

I agree with Craig that OMF is not a great format to use.  I have tried this with a couple of album projects and it just didn't work well.