I bought this mostly as a just-for-fun project to do one day. I haven't modified my engine in any noteworthy way, and it's attached to a CVT, so the torque converter just being there doing torque converter things isn't going to let a part like this have any chance of putting a dent in the rotational mass the engine has to deal with on my vehicle, so I can't attest to any track time improvement or dyno gains.
However, it IS a well-crafted piece of metal, lighter than OEM, and available in a few colors, so there is certainly enjoyment to be had here. On my engine, this is the easiest pulley to replace aside from an idler/tensioner.
If you're going all out on a build and are looking to reduce the weight of the parts the engine has to spin, this will do the trick and look good doing it!
I can also say that, after having this on my daily driver for at least 40,000 miles, the belt ribbing alignment is really good; I haven't had any issues with wear or noise from the belt, pulley, or water pump bearing.