Right now I think it’s difficult to judge some of them because they only recently joined XGS and don’t have a huge body of post XGS work. The standout studios right now for me are, in no particular order:
The coalition
Playground
Bethesda Rockville (Todd Howard’s studio)
iD
Obsidian
Arkane Lyon
Studios that get underrated:
Rare
Turn 10
Undead Labs
Studios performing below where they should
343i