The stock DJI transmitter is a toy compared to the Futaba's. (and I'm not really exaggerating either).
If you're hooked on this hobby, the sooner you can get into a better Tx, the better off you are. (same with a battery charger, of which the DJI is also as crude as they come).
The Futaba's (and spectrums too I imagine), have better connectivity, better range, timers to help keep track of flights, real knobs up front to adjust gimbals, trim functions, and p-mix functionality and switches so that at the flip of a switch, your sticks will be half as sensitive (ideal for doing smoother flying/filming).
But honestly couldn't tell you which is better to go with, as I imagine the 14SG is quite expensive, might be overkill for a Phantom.
unless you plan to accessorize or move into a larger copter at some point.