It is all up to personal opinion. Those three titles could have sold 30,000 units each and made operators richer than Mr Trump.

I'll go back a step - back into my preferred era..

Eight Ball (1977) - 20,000 units sold. One of THE most requested titles. Not one drop target and it is a boring game.
KISS (1978) - 17,000 units sold. All time favorite band, yet the game is BORING. Coin box emptied every 2 days.
Mata Hari (1978) - 16,000 units sold. Nice looking game that resembles many GTB EMs (Spirit of 76..) - Not seen much these days (parted out) ?

Paragon (1979) - 9,000 units sold. BEST SS ever produced. Slowly becoming the most sought after SS of the era.

I'd rather own a Paragon than the other three.