I enjoy that it is up to 4 players. Other games that are competitors really lose out on this, especially Pillars of Eternity.
As I stated during D:OS2 Vs PoE2 thread back on Obsidian forum, those are different games. A bit like left4dead Vs Doom. What you prefer, will be based on what game you are looking for. From my perspective it is Larian who is behind the competition in their narrative design, companions, quest design, worldbuilding and overall playability.
But yeah, if you are looking for a coop RPG no one does it better then Larian - mostly because no one else really does it. At best it is coop functionality added to a single player game, while Larian adds single player functionality to a coop title.