Ryan in this topic did a bit of comparison using a laser between the Rambo and the SKR Pro. The SKR Pro has a 32-bit processor with built-in math support, so it is able to handle the laser at a somewhat faster rate. I don’t think you will see any difference when milling. The SKR Pro is a newer additions to the V1 store. It comes with a TFT screen, which many people like, but has been a source of some troubleshooting at times on the forum.