Ask a PSG fan if they're in favour of VAR, after what happened to them in the dying seconds of that United game. You can still get royally screwed by a duff VAR call on a marginal decision.
It'll get some stuff right, but not everything, because it'll still always boil down to human interpretation. Sometimes you'll fall on the wrong side of it, sometimes on the right. Isn't that what we always had before VAR anyway ?
What you gain in the chance to get more correct decisions, you pay for with sometimes multiple delays with the ref standing around with his finger in his ear, and the crowd not always knowing whats being reviewed or why. VAR reviews on goals particularly suck, as all the celebrations go on hold until the ref eventually points to the centre-circle.
It'll change the game massively, but not all of it in a good way.
Worth noting it was not a duff call and was correct as per uefa’s briefing to the teams about how VAR would be and should be used. It is not uefa’s fault that the British pundits like Rio Ferdinand don’t understand the rules.