Pgsql v10 works perfectly for us (although our forum is tiny so it may not be a good test case). @Ben-Lubar however, did a number of performance comparison to mongo-DB, and it looks like pgsql is on par. You can follow his work in tdwtf. Good luck!
@julian Cool thanks, yea poor ns-embed is not happy in 1.12.2 - I and others already flagged in that thread, still, A Great plugin!
Ok SMTP/EMAIL is fixed!
Some deeper DNS/MX work seems to have made the difference and using "encrypted" setting - initially I was using StartTLS as per email provider SMTP guide, which specified TLS - tested it again and StartTLS broke it.