I have no concern about left turns into Super U. It's a great store, but I rarely visit. I think that I've only been there once.
Me, I get around. I shop small when I can, and know where to do it. I'm not against Super U, I just prefer to shop small, which is often closer to the old St Barth.
I still shop at Mono Shop, Jojo, Mini Mart, and Superette before I consider shopping at Super U. Also, AMC in Gustavia if I'm at that end of the parking lot, Épicerie des Cayes if I happen to be down that way, Épicerie de Corossol if I just want a few things and a classic sandwich.
I will not speak of the secrets of Maison de Plantes. If you know, you know. If you don't know, well then...
There are a few others too. For some, I point them to La Vie Claire, the organic grocer above Anse des Cayes. There are a few other tiny neighborhood groceries which still survive, as well as Le 'Ti Marché in Lorient.
As to Mini U in Lorient, I would be crazy if I didn't shop there from time to time. It's usually on my way from/to everywhere, but it's just not my first choice.