I've never found the beach nor food to be hit or miss as you posted. Are you confusing Grand Case with another area? Harmony Nights is on the main street.
Many restaurants right on the beach, others across the street. There are a couple of LOLOs cooking outdoors and outside tables. Maybe that's where you heard "hit or miss"?

Many boutiques along the main street and there's TiJon a place where you can make your own perfume or just watch some being made. Check with Grand Case Beach Club web site to see if the watersports center there has options for non guests. They also have good restaurant on their property that is open to the public. It has a great view of Anguilla and a nice beach where they will serve you at chairs which can be rented from them.