Best is in the eye of the beholder. If defining "early" as games from 1977-1981, they were advancing every year with better sound, playfield layouts and rule sets. I roamed arcades and played most released during that period. Have owned dozens since. Many had great artwork but were lacking in game play. It isn't fair to compare a 1977 Eight Ball to a 1981 Centaur. That's like comparing a 1980 VW to a Porsche. Both German engineering but night and day different in performance. Dollar wise for the fun factor my pics are:

1) 1977 Eight Ball. Bang for you buck, almost 20K made. Nice examples are under $1200. Great artwork. You'll never lose $$ if you buy right.

2) 1979 Harlem Globetrotters, same as above, cheaper to buy.

3) 1979 Meteor, great player, lots of fun, cheaper to buy.

Money no object choices:

1) Fathom, best of the best, open your wallet wide.

2) Centaur, Owned it sold it. Great game but like owning a vintage MG, lots of stuff can go wrong.

3) Flash Gordon, personal favorite for price vs fun.

4) Embryon, best wide body ever, sorry Paragon ( I own Paragon)

5) Nine Ball, crazy hard rule set but a blast to play. Anyone selling?

6) EBD, very challenging game that still hasn't gotten crazy price wise.

Many more I could list that are great games I love playing.

Please, no. Pinball enjoyment is a personal thing. I don't give a crap what someone says about a game till I play it myself. Everyone has different things that bring them back to play it again or walk away. Pinside's ratings (and IPDB) are based someone else's pinball idea of what they enjoy. I like drop targets & fast playing games. That's just me. Some like slow games like Space Invaders which to me is boring as hell. Great looker but a snooze fest player.