I agree that (in my experience) DL has by far the best record in posting points. When flying DL the points post before you arrive at your destination. Sometimes DL's various bonus point promotions take a while to post but my experience there is 100% also. I don't even recall any problems getting partner airline points posted.

AA is pretty good also but they have more problems with partner airlines. I've sometimes had to wait several months for some to post(still waiting for some JL points from Feb).