dear hh:
welcome.
about mozart, i agree with you that most recordings lack "something", what sometimes it's even difficult to say what is.
anyway, i really like two versions of the complete cycle. first, and foremost, the one by mitsuko uchida, one of the greatest mozart performers i've ever heard. i think she have all the qualities of tone, expression, virtuosity...anything that mozartian text calls for.
for a contrast, a very idiossincratic version, that however amazes me: gleen gould. probably anything but authentic, but never boring. you'll probably discuss 90% of what he did, but he have a very solid coherence in his interpretation. furthermore, it stands among the bland mozart that were (and are) around.
another great performer of his works (although i don't know if he recorded the whole cycle) is andras schiff.
best!