I've been here to the 538 Jingle Ball event which was sold out. The place is huge but still safe and the line to get in wasn't that long. There are more than one cloakrooms so don't wait at the first one because that one will take forever. Prices for drinks inside are high just like on most festivals. There are ATMs inside. You can park outside on the parking lots (5 minute walk) and the price is reasonable, 12 euros. Enjoy!