I will preface this by saying that I don't know a lot about the QS dining plan. I don't know how many meals you get with the plan or how often YOU dine out. But for US, we would go OOP.
We tend to eat breakfast in the room before we leave, so no meal needed there. We stop and have a snack mid-morning, eat a later-ish lunch (we share) and then have a normal-ish dinner time. Again, we share. We maybe have another snack before bed. Since we only eat about 2 "meals" between the two of us, and a few snacks, I'm not sure we'd get our money's worth out of the QS plan.
We definitely save money getting what we want OOP instead of maximizing the use of those credits. I feel much happier getting what I want instead of thinking, "this isn't a good use of xxx credit" or "I am not hungry enough for this meal to myself, but we need to use these credits up." Everyone is different, so the QS plan may suit your needs better.