I don't know the Boxer. Does it run Open TX or Edge TX? What's the advantage of the Boxer over the TX16S?
Regardless, it's going to be drastically different than the FSi6X. Much more versatile, but not quite as intuitive, IMHO. Spend some time going through the Edge or Open TX tutorials on youtube. It's not really what I call harder than working with the FS radio, just different.