The strengths of this SDM are also its weaknesses. It has a great location, and it's 24hrs. This means that it's a hugely popular location.
Things are always out of stock, especially things on sale. I've definitely gone without milk because they were out of stock on milk. Talk about a first world problem: my 24hr convenience-pharmacy doesn't have any pasteurized milk for me to buy at 1am!
I've talked to the staff, and have learned that they get shipments every day except Mondays, so if you're looking for a popular item, you know when to visit.