You must fly a different UA out of LAX than I do. I've actually found them to be the worst. DL does struggle with congestion issues, particularly during rush hours. Seems to get worse if flights start arriving early or late as their well-choreographed system falls apart. Still, it beats remote off-loading.
A couple of airlines are hanging out over in T-6. Are they subletting DL, CO or UA gates? If DL could get an extra gate or two over there it sure would help things out a bit.