Caleb and John have provided great responses.
Mine is: “No need to fix what isn’t broken.”
C3D has a few unique features like streaming jobs so no set max size (unlike Ruida which stores jobs and has a 128MB or 256MB controller memory limit), native rotary support (on Ruida you have to unplug the Y motor and plug the rotary motor into that.
On the flip side, Ruida is faster and has a few more industrial features that the C3D does not.
And yes, C3D LaserBoard has embedded Trinamic stepper drivers which are amazingly smooth and quiet, but all DSP’s including Ruida only feed step, direction, and enable signals to external drivers for larger, higher power motors in bigger machines (the C3D can drive those too, but worth noting this difference).
Since you can already use LightBurn with your laser, I don’t have to sell you anything.