Confirmation Re MP9B knees

I've been out of the loop for too long regarding this guy :p

I nabbed one of these MISB recently, opened it up last night - popped off the thighs to confirm both knee joints have a clean crack on the weak point. The good thing is the cracks give the hinges looseness so that I can get a couple of notches of articulation quite easily - of course I didn't test bending all the way knowing that they just crumble.

Anyway, I know both plastic and metal replacement knees exist - I just wanted to confirm that metal knees is the way to go? Or are the plastic ones actually quite good in their own right?

I got printed joints from a us guy before the metal were available..... And they are fine....

But if I ever see the metal I might swap