I have always thought that DOE angle wrenches were primarily prized by tractor guys and those that work extensively with hydraulic lines.
Quality angle wrench sets always seem to command terribly high prices. I fell into a smoking deal for a set of Snap-on, either 5 or 7 piece for some insanely low price so I bought them. I already had several sizes going down to 5/16.
Funny though, I have not used every size, and only one or two of the smaller sizes on e or twice. That said, it is still a beautiful set and of course, I don't regret buying them.