We just returned from Aulani. Pre-check-in seemed convenient, but the check in person FLEW through the introduction, greeting, mini-tour, and then handed us our room packet with keys.
We had booked and expected ocean view villa (6th floor or above), but got partial ocean view on Marriott side. Great view of the street and Marriott property; had to look past or around it all to see the water. The only option was to check out the next day, store our luggage, and check in after 4PM. Hardly a "welcome home" for a
DVC member.
This was one case where the online checkin did not gain us anything, and may have hurt our location. I wish we had taken the time to visit the front desk and understand our location before going up. We arrived late in the day anyway, and there was no backup at the desk. If we had had time to see, on a map, where our room was and what it overlooked, we would have demanded a different room immediately. Much wiser for the experience.
Have safe travels, and enjoy your vacation!