I think perhaps I identify with Sunrise better because the characters in that film are closer to my age, before the weight of the world crushes their dreams. I found Sunset a little sadder naturally, but the ending I thought was absolutely charming. I just think that Sunrise showed that the concept actually being in love could happen in our generation, despite what we may have thought. Sunset kind of shattered that illusion to me, but it showed a different kind of truth. Not sure what a third would be like, but then again I wasn't quite sure about a second.