I really enjoyed watching Clementine's tale unfold over the course of The Walking Dead Season 2. It managed to establish a different tone than the first season, which makes them rather hard to compare bit by bit.
But in terms of delivering a suspenseful, emotional finale, I think Lee's final outing takes the cake. Season 2's No Going Back is the last time we'll see Clementine for a while, but for the most part the episode deals with many of the same themes we've seen in her adventures so far.
Not that it's a bad thing, mind you -- just don't go in expecting it to blow your mind.