After several months of running that same old "oldham" coupler everyone else uses, I saw this and thought... pure genius. I had to try it. Everything printed easily and assembly was a snap. I did have to file and sand two opposing sides to get the bearings snug enough to remove the "twist error" that vascojbd spoke of, but once I did that, there is almost no twist at all - nothing visually perceptible anyway.
In the photo I've uploaded of my test tower, you can the vast improvements with each modification I've made. From left to right, the first tower is prior to my latest upgrades. The second tower is after installing this no-sanding oldham coupler. The third tower is after installing my upgraded x-axis motor mount. As you can see, the improvements realized just by installing this coupler are phenomenal!