We recently rented with National... We arrived 11/30 @ 11pm - sure enough, the only cars on the aisle were Mitsubishi Lancer's!! That's an economy car!! No way could our stuff fit in the thing. There wasn't an employee ANYWHERE, no where at all!!! My husband took one of the mini-vans around to the check out booth & asked her what the heck he was supposed to do!! The minivan was NOT in EA by the way, but he chose any vehicle they had to drive over there LOL... They told him to go back and pick our an SUV, so we picked the one they had - a chevy blazer... it worked out okay, but by the time we left, there were easily another dozen people, also picking out whatever premium cars they could find... there were no full size cars at all... Actually, there weren't many cars at all... I'm sure that anyone that came in at midnight found nothing to be had....
We did have a backup reservation through Dollar for a full size vehicle, but it would have been a bit more... I wouldn't use EA unless you had a backup plan....