I've been here a few times since they've opened including their opening weekend and so far it's been excellent customer service. Their mobile app really helps kill the pathetic long wait time - not to give away my secret but honestly it does make it faster to get in and then out.
My only real complaint so far would be the time I ordered a Large Milkshake and they gave me a Medium. I didn't bring it to their attention because I didn't have the time to wait but why charge an extra 40-50 cents if you aren't going to provide the larger size?
Other than you can't expect a brand new restaurant to be perfect. The police helped them out for a good solid 2 weeks I think and now they seem to have it down. Why else would people actually waste their time and money coming here for FAST food if it wasn't good?