We ate here twice during our stay in Arromanches. It wasn't bad, but nothing memorable. The service was prompt and nice enough. It's a large restaurant with a lot of volume, so it felt a little impersonal and rushed, which is uncommon for France. Still, it's a tourist town and most of the people who come here aren't interested in the hours-long French dining experience.
The food was good and basic. If you're looking for something quick, but substantial (i.e. more than just pizza or crepes), Brasserie Au 6 Juin is passable.
One thing to note: If you see a table on the outside terrace and that's where you want to sit, grab it. Don't wait for the staff to seat you there. We were polite enough to ask in advance and while we were busy asking, someone else sat at the table we wanted. Because our French isn't that great, we couldn't dispute that we had asked for the table ahead of the couple who simply took it.