The blow-off to the Augments arc (conveniently named "The Augments") is the most satisfying installment, benefiting from the material that has come before it, which one would hope from any series of episodes.
Prior to this, it should be noted, the only time Star Trek had specifically done a series of three episodes for any one story was at the beginning of Deep Space Nine's second season.
Arik Soong becomes relevant, and his own arc more significant, in the conclusion to a desperate bid to shut down a group of genetic supermen reawakened from the batch that originally gave us Khan. As I've said in previous comments, the whole point of this story is to provide links through the franchise, and Soong is established not only in connection to Khan, but officially to Data as well in the episode. You can imagine a lot of stories to be based on the elements of the Augments arc. Enterprise would itself do one with the Klingons several episodes later.
franchise * series * essential * character
Memory Alpha summary.