The pairs were Mohinder/Eden; Niki/DL; Claire/Mr. Bennett; Peter/Isaac; Hiro/Nathan? So if one of each of these is "better" does that make the good guys Mohinder, DL, Claire, Peter and Hiro? And the bad guys Eden, Niki, Mr. Bennett, Isaac and Nathan? Or is this title just a reference to Niki's split personalities? The title is plural, . . .

I think it is either a reference to DL/Niki or Niki's split personality.

I think it was more of a play on words referring to the Niki/DL and the Niki/Ikin interactions.

I think it's a comparison of the dead guys in the apt vs those in her garage.

"Better half" has two meanings. The most usual is a term for one's spouse. In this use, DL is Niki's "better half." The second use is specific to this show. Niki and Jessica are two halves of the same woman. In this second use, either personality would consider themselves the better half.

I think your suppose to make of it as you will. Means different things to different people.

guys the pther half of nikki is jessica...it was established in the online comic