We can all give it a grade, the main question is has it been a net good or a net bad - leading to persevere or pull the plug?
List all the instances VAR has righted a wrong (a lot). Offset that with the times it's caused a good decision to be overriden by an error (a few). We know it's missed chances to right a wrong (like Kompany last night) and they'll have to be much better than that. My main worry was delaying the game with the time it would take. I've been pleasantly surprised. Watching the NBA, I'll shout at the screen over the delays and they've been at it for years. With a few exceptions VAR has been quick enough.
Think about Maradona in 1986, Thierry Henry's handball against the Irish, even back to Leeds v Bayern Munich in the euro cup final. It's use would have changed footy history. The impact is huge.
I like it that far more penalties are given. It's going to lead to far less holding at set pieces and that's got to be good for the game. It's almost impossible for refs to police that and it would get even worse without it. One worry is the on-pitch refs changing. They can't start leaving penalty decisions to VAR. They've got to think that being overturned for not giving a penalty is as bad as a given penalty being corrected - just do the job as normal and not be influenced by VAR.
Brave decision by FIFA to bring it in for the biggest show in the world and I think they've been vindicated. There's been at least 1 disaster day for VAR, but you can be confident that those officials won't be let anywhere near today's games, semis and finals, but I'm ready to proved completely wrong...