Flash graphics are awful. Back in 1980 I asked the operator for a Lost World which had brilliant art work. He did not have one so I opted for Flash. In terms of game play and challenge, Flash was a better buy.
Centaur is a really god machine. Played a new one at UTS in Sydney in 1982 where the students killed some time in between classes.
There were Centaur, Kiss, Black Hole, Meteor, Hulk, Haunted House, Supersonic and Flash Gordon. Just up the road at Broadway there were many pinball machines but my favourite was Firepower (one operator had 4 on the same site). He had them cranked up real loud and you could hear them up the road!