I can only talk about about Games I remember but Melbourne, Rome and Tokyo 64 all have good reputations from those who remember them.
68 was spoiled by the effects of altitude, 72 ruined by terrorism, 76 was just average and 80 and 84 ruined by politics and rampant drug taking.
Now to those I can talk about.
88 was a good Olympics but Barcelona was a fantastic Games. Atlanta 96 was great as long as you were watching on TV but the athletes and spectators were treated badly if you were there.
Sydney was just magnificent, Athens OK, Bejing good, London almost as good as Sydney, Rio was fine and it's not fair to judge Tokyo 2021 because of Covid.
My top three would be
1 Sydney
2 London
3 Barcelona
But it depends a lot of where you come from and the problems with time zones