jtsangnj First let me say I appreciate Echo's efforts to fix and upgrade a common weakness on Hercules. This review is meant to help possibly release a new better revision.
I just received these parts and installed them with the metal hip replacements. Fitment and design was very good. At first Hercules legs moved up and down with slightly stiffer ratcheting and seemed better than the original parts. But after about 4-5 clicks, the ratcheting weakened significantly and Hercules legs can barely stay in the up position. They start to flop back down. Upon inspection on what went wrong, the plastic tooth that makes contact to the hip gear wore out (see pic). In my opinion this shouldn't have happened so quickly and only after a few clicks. The plastic material is clearly too soft to handle the ratcheting of a metal gear on it and a stronger plastic should be used to print this part. While this came with 2 sets. I strongly believe using the second set will have the same result.
To resolve this I made my own out of grey PVC which is harder than nylon and so far it has outlasted these parts.
But as for the metal hip replacements I would recommend getting it. Big improvement over the original plastic part. But just be prepared to do some finishing work for proper fitment.