I don't think it really matters with the knuckle joints, its ball joints you don't want to cheap out on.

I finally got my cones out and now it's time to put in new trumpets, cones and ball and cups (I destroyed the last ones in the recovery). I was looking at minisport and looking at GSV1118 - $21 each vs 21A1163 -$12 each. For every day driving, does anyone have a particular reason why the 'genuine' one is preferable over the cheaper ones? I'm trying to quantify why I should be buying the more expensive one. I did a bit of digging but all I could find is that the GSV is considered pre 1990's, whereas there's nothing special said about the 21A.

Thoughts?
Cheers

I would buy 'genuine', as most of the real cheap stuff is inferior quality from China or India (in several other parts I could mention, made from cheap rubbish steel, plated to look pretty and not hardened).
If you have a choice these days, pay the extra, you may get Quality.

Kc's knuckle joints were fine last time I bought any.
Note they have (ahem) lower prices than some other Mini suppliers here in Oz, because are primarily parts wholesalers for a variety of vehicles (eg land Rover) and don't have a fancy retail website to support.