i prefer the iroc boxes my self. all my cars run them. why you ask?
first, they have one of the smallest pitman arm swings of that steering box generation. irocs have a 64 degrees of swing, regular f-body gears are 70 degrees.
by running the smaller swing, i have no or less issues with front tires rubbing the fender or fender liner at max turns.
second, by having all my cars running them, the steering is more consistent for me when i jump from one to another. yes i do loose some turning radius, but i compensate by swinging a little wider and turning a little earlier. you don't notice it once you get used to it.
i buy all mine used, mostly u-pull yard finds, and craigslist. all have worked fine and no leaks. maybe I'm just lucky.