Just had my first experience flying Oman Air now that they are part of One World.
DOH-MCT which is was uneventful
At DOH there was a priority line but they asked me if I did online check-in so it wasn't 100% that my status let me into the faster line.
Our baggage was given the priority tags
Lounge access was the Qatar Gold lounge. They actually refused us at the Silver lounge.
Priority boarding was normal.

MCT -DOH was a lot more interesting.
Specific area for business class check in, business class immigration line and access to the Oman Air Business Lounge which is not part of Priority Pass so a lot less people inside.