Okay, so this one might be a bit of a cheat. Liara isn't exactly an 'underrated' character to romance. But from what I've seen, most of the romance-related discussion goes towards Tali, Garrus or Miranda. And to me, that's overlooking the best companion in the whole franchise. What makes the Liara romance stand out from the others in the series, and from other Bioware romances, is how it forms a narrative through-line across the entire saga. Unlike many other characters, Liara can romanced in all three of the games, and is thus by far the best developed. She changes drastically, starting out as a shy, bookworm of a scientist in the first game, before then turning into a ruthless information broker in the second, and in the third manages to balance these two parallel opposite sides of her personality. It all serves as a great foil for Shepard, who, no matter whether you're male or female, paragon or renegade, or whether you follow her romance path, has feelings for them. Even after Shepard 'died' in ME2, she went above and beyond to retrieve their body and help them get resurrected, all whilst Shepard's other friends moved on. In fact, shes probably the closest thing the franchise has to a canonical love interest. After all, who can resist the charms of an Asari?
