I beleive the only difference is that the Richmond sets are forged and then nitrided after machining, this is the ultimate from a strength and durability point of view. The no-name brand versions are heat treated castings and are the same as the factory original gears. Unless you are drag racing all the time and run a high horsepower engine(400+HP) with a standard trans the lower cost versions work well if set up properly.
“She may not look like much, but she's got it where it counts, kid. I've made a lot of special modifications myself.”
— Han Solo