I entered the US yesterday with my immigrant visa as a DV lottery winner. My POE was Dallas Fort Worth international airport.
Total duration: approximately 90 minutes:
* 70 minutes waiting in line in the "Visitors / Foreign nationals" queue. I asked which queue I should follow as a first-time entry of an immigrant, and they pointed me to the visitors queue.
* 5 minutes primary inspection, with digital fingerprinting and picture taken. Only question asked was "who sponsored your visa", to which I answered "nobody, I won the visa lottery".
* 10 minutes in the waiting room for secondary inspection.
* 5 minutes secondary inspection. No questions asked, just fingerprints of right index finger taken with ink, and I had to put my signature on a form, both for reproduction on my green card. The officer showed me the stamp endorsing my immigrant visa. And that was it.