Seems like all the 5 star reviews aren't very specific at all, whereas the 1 star reviews detail a 2-3 hrs wait (no appts, apparently). If I bring my car in 20 mins before you open, can I be taken care of immediately or will I be told 2-3 hrs?

You're right. No appts. If you arrive before they open you will join others waiting for them to open. Depending what you need it could be 2-3 hours or all day. If ALL you need are tires go to America's Tires. They are super fast and less expensive than Big O.

I'd call ahead to get an time estimate for that day. I usually uber home and come back. Although They do have a shuttle. I trust these guys... That's priceless to me and ,that's, worth a wait.

Call the location and ask them..