I just recently returned to the US and for the first time got to go through the citizen's/residents line (Green card holder), and the difference between the two was unbelievable. This time round, the queues were a fraction of the size, the immigration officers were friendly (as opposed to being outright rude to visitors) and the whole process was incredibly simple and quick. The difference is striking, and I'm certain it's not just me - visiting family always complain about how long immigration takes.

This doesn't jibe with my experience as a Canadian H1B visa holder who's flown into the US over a dozen times over the past 6 years. I've never found US customs agents to be rude; they are always courteous and often friendly. FWIW I usually fly into LAX so I wonder if your experience differs depending on where you enter.