VAR has been a mixed bag at this world cup, but I think that was always inevitable considering it was the first World Cup it has been regularly used at, I don't, however, think it deserves the label of a "Farce" as described by Shearer or a "Shambles" as Milner put it.
I think, in particular, the Iran - Portugal and the Spain- Morroco games were the best examples of how VAR can get things spot on, and how there are still improvements to be made. It seems that something designed to reduce the sense of injustice and foul play in football might actually end up making things worse. I think one of the worst decisions was Ronaldo's off the ball elbow against Pouraliganji, where Cristiano was given a yellow for what was obvious foul play. Another incident that comes to mind is Aspas' goal being allowed after an initial offside call. Whilst Moroccan's were incensed, it was the right call to make.
Overall VAR was best used when concerning goals scored, see Diego Costa vs portugal, Ezatolahi vs Spain and Aspas vs Morrocco. Red Cards and Penalties, however, have been a much more mixed bage, in particular , Rebic on Salvio in Croatia vs, and the Non Dismissal of Pique.
I think what FIFA need to do is remove "clear and obvious" from the wording of the regulations as this leads to confusion with regards to what the VAR refs should and shouldn't be looking out for, and obviously different individuals definitions of "Clear and Obvious" are going to be different. I also think VAR could be used to remove weak minded and ineffective referees, such as Caceres from officiating. His use of VAR proved to the world that he is an inept referee and weak minded.