I’ve been in the US numerous times and I’ve commented before (probably on here) that I think US restaurant food is almost universally better than similar fare here in Ireland. It depends of course because the restaurant culture is slightly different, but by and large American restaurant food is superior to Irish in taste, portion, value, and most importantly to my mind, the level of service attached (although that’s hardly germane to this thread). The only universal counter example I can think of is that Johnny Rockets is disgusting versus its Irish knock-off Eddie Rockets.
Conversely, while most things are cheaper in the parts of the US I’ve visited than here, I feel that quality dairy, meats, fresh produce, is cheaper in Irish supermarkets. However, this is a relative thing. While some foods are indeed actually cheaper in a supermarket in Dublin, IRL, than in Dublin, OH, it’s more that relative to other price differences the gap is much narrower, and often, the equivalent product here is better. Saying that, quality of supermarket food, presumably varies enormously across the different chains, and $ you’re willing to spend. I’ve had plenty of quality supermarket-bought food while visiting the US and the array of fare available often beats what’s on display in a typical supermarket here.
(FWIW, I can think of only twice I’ve had meals in a restaurant that were close to inedible. Once in an “Italian” restaurant in Dublin, another time at an American chain restaurant in Niagara Falls, Canada.)