Glad to hear they've improved their customer service where early check-in is concerned. I've only stayed there twice both times for a convention held at MB. These stays were 2 and 3 years ago. Both stays, the check-in staff was nasty and rude. There was only my party of 2 and another couple trying to check-in at the time. Basically we were told come back at 4pm and not a minute sooner. I would of thought getting a couple of rooms checked in early would take a little bit of pressure off when the mob of people showed up at 4pm to check-in.
Other hotels haven't had a problem with early check-in if rooms were available, but if not we've been told politely to come back in an hour or two and a room should be available. Or as raaajaaa said given us generic keys so we knew we were checked-in, just didn't have a room assigned yet.
I stayed comped at Caesars now and get to MB easily on that frontage street(Frank Sinatra drive maybe) between the 15 and the back of the hotels. Valet parking is a lot less than paying for a room at MB.