I had never heard of Open Pit until I saw it at my local Publix. But after poking around a little bit online, I learned that apparently it's mostly found in the Midwest, specifically cities like Detroit, Chicago, Milwaukee, Indianapolis, and Pittsburgh. And it's no new kid on the block - it was introduced in 1953.
One other interesting thing is that the website repeatedly encourages users to add their own ingredients to the sauce, even mentioning that using the sauce "right out of the bottle" is the exception. I have not ever seen this kind of thing emphasized before.
As for the sauce itself, it is a brighter color red than most commercially available barbecue sauces. It's fairly thin, pouring readily, and has a completely smooth texture. The aroma of the sauce is interesting. Of course there is a tanginess, but there are also notes of cinnamon. Upon tasting, the first reaction is that this tastes like very tangy ketchup. The tomato flavor is bold and bright, and the vinegar is tangy. At first, you sense that the sauce is sweet, but the sweetness soon fades, leaving a stronger impression of tanginess. Then come the more interesting flavors, a rich savoriness, plus notes of onion, garlic, and once again the faint flavor of cinnamon. Finally, a hearty heat sets in, providing a bit of mild burn. If nothing else, this sauce is different than any other you'll encounter in the supermarket aisle. I rather enjoyed it.