I bought mine from @dlang. It’s been working pretty well for me so far, although I think that my performance is going to be worse than if you follow his instructions instead of going off the rails like I did. I still need to figure out a better hardware setup than I’m currently using because it’s introducing errors into my linkage system. See the top mount thread for more details.
I plan on buying one of @pillageTHENburn’s kits and doing some comparisons at some point.