I used the online C-5 when I landed in early November. The line was all the way down the stairs but when I finally got to the top, everyone from my plane went to the kiosks and I just walked passed then. Took the straight line right in the middle that walks you right up to the front of Z lines and I was at an immigration desk 30 seconds later. Immigration officer found my online form after scanning my passport. All went well. The only issue was when I got to customs, I told the lady I had filled out the C-5 online. She had to reboot her computer, which took many 3- minutes. She just said very few people do it online, so when someone comes along that did, the computer went to "sleep".

Also, the first rule of walking through the airport, never ask an employee what to do or where to go. You will get an incorrect answer 100% of the time. I think it might even be a bit of a game with them. Stand here, don't stand there, go to this line, this line is closed, blah blah blah. Welcome to Jamaica within 5 minutes of getting off the plane.