Flamingo Auto Check-In

Staying at Flamingo Feb 16-20 in a GO Luxury Room. Have read about long check-in lines and also machine check in in lobby. How does this work? Do you get a choice of rooms, or does it just spit out the next available room in your category. Not looking for an upgrade, as we have booked the GO room, so no need for $20 trick and a long line. Does the machine give you your keys, and are there other factors that you can enter (e.g., near elevator, non-smoking, etc.)
Thanks

The three times i've stayed at the Flamingo there has been a *gold* check-in line. Short and sweet. Last time was in June...

I'd like to know more about this "auto" check in machine. We quit staying at the Flamingo because of how we were treated at check-in on our last stay there.
At the time Platinum were allowed to use the separate "Diamond/7 Star" check in room but we had arrived when it was closed. We stood in a very long line, had a very surly clerk who said I was "only" Platinum and because I wouldn't pay to upgrade to a GO room and got a terrible room. We haven't stayed there since.

I've used this machine twice now and bypassed the always long Flamingo lines, only disadvantage is you can't "negotiate" with a computer. It will give you the room type reserved, but one time offered an upgrade (for extra $). It will let you pick a general region of the hotel, not a specific room. It'll then spit out two room keys and you're on your way...love it! If you don't like your original room assigned, you could always call the front desk and try to switch afterward.