The main issue is compatibility with your existing controller. Obviously the 790 is made by company A and it is then made available to many 3rd party sellers. Each variant will have pcb which is programmed and installed at a central factory for the customer or the customer might buy the 790's in and install the pcb on their own production lines.
As I mentioned 8fun, Lishui, KT and many others use the generic 790 style but none or very few will work with each other. A basic analogue (4 wire ) should but once one has the 5th uart/digital wire compatibility raises it's head.
As I mentioned 8fun, Lishui, KT and many others use the generic 790 style but none or very few will work with each other. A basic analogue (4 wire ) should but once one has the 5th uart/digital wire compatibility raises it's head.