Of course it's subjective, but you must not understand good musicianship and songwriting if you think The Postal Service was/is better than Death Cab.
They put out one good album with a couple great tracks, I enjoyed it, and still listen to it. I'm excited for what 2013 holds.
However, there are single songs by DCFC that in of themselves are better than TPS as a whole. We are talking about a band of four extremely talented musicians who defined a genre compared to their singer's whimsical side project that happened to be pretty good.
It's all personal opinion really, just because I say that doesn't mean I don't understand good songwriting/musicianship. I like DCFC, I just prefer the glitch-pop of TPS more :)