VAR vs TMO (Rugby Union)
Although the TMO system is not perfect I feel that the majority of people in the game are happy with it, or at least no major gripes because at the end of the day we all want the right decision to be made and it is a very hard job for an on field officiating team to see everything.
TMO - On field decision rules but if something is obvious that the ref may have missed then it is looked at, i.e. the ref sees the ball grounded but 2 phases before that somebody tackled off the ball or an very obvious forward pass. These cases are looked at as quickly as possible, the best angle of each incident is attempted to be found as soon as possible.
VAR - On field decision means nothing. Everything is looked at, regardless of how obvious it looks. Even when it is obvious it is looked at from every angle, sometimes an angle that tells nobody anything and then you get somebody who has never operated any video technology as there is a random zooming in and out of those angles that tell us nothing. i.e. Beto offside check against Man Utd, pretty obvious that he was onside when the original ball was played, it was nowhere near close to an obvious mistake if the secondary player even touched it, if he did it was so minimal no camera could pick it up, then the offside in the first phase of play. Obviously nowhere near the ball when played through, so by the letter of the ball not even close to an error by the on field officials.
All in all, 3 checks there, which is, in some cases you have to say it is needed to get the right decision, but each check should have been 10-20 seconds at the absolute max, instead of the 5 minutes it took for all of them. All because there was no clear error from the on field officials and it was obvious to see this from the first angles shown.
I suppose the main difference in Rugby to football would be that the conversion needs to be taken, so there is a natural (up to) 60 seconds stoppage in play. This is the only difference, but these checks are still so much better when the play is still ongoing.