Yeah, Descent Part II may have the emotional impact of the Data-Lore story, but frankly, it makes the Borg into little more than your standard issue grunts - they could honestly be anybody. The second part takes a story that was interesting on it's own, the idea of the Borg developing into a violent aggressor species, perhaps even with the idea of making Data into their king, and it turns into another tale about the brothers of Soong. To be perfectly honest, I was never big on the 'Data has an evil twin' story, so there wasn't a lot in the way of 'emotional impact' for me. Really, the highlight for me was the 'Crusher in command' story.
I'd give Homecoming the win.