The features that I'll personally probably enjoy the most are really the FDW join pushdown work, parallel query. (though it's still early days for the parallel stuff)
..and the thing that's a killer feature for many larger databases, the freeze map. Not having to FREEZE things all the time is a godsend.
..and the thing that's a killer feature for many larger databases, the freeze map. Not having to FREEZE things all the time is a godsend.