When DH and I went to 'Ohana in January, we were in line to check in. We had a 5 pm ADR but the 2 couples in front of us did not. We started to line up at the podium around 4:20, BTW.
The folks who dod not have an ADR were told they could wait standby but it could be 2-3 hours and they both decided to wait. (I listened, I'm nosey!)
Anyway, DH and I were seated promptly at 5pm. We noticed that the first couple got seated by us after about 45 min.
After our meal, which we got done at 7:30, we noticed that the second couple was still waiting for their table. Personally, I wouldn't wasted precious Disney time waiting that long for a table for dinner.