I have one machine from 68 in the collection...
quirky is how i would describe it
http://www.ipdb.org/machine.cgi?id=1774But if you want the best game from 68 then i would recommend a Bally game... zipper flippers are just about one of the coolest features to ever be introduced to pinball and i think 68 was just about the heyday for these.
I would
almost recommend a WMS HAYBURNERS2 ... zipper flippers and great backglass animation, however, previous promises to myself prevent me from recommending a game that has NO bumpers!