Here's a more detailed review and at about the 12 minute mark he even explains how the "coil split" works.
It's different than what you might think. Different than I thought anyway.
The PRS coil split sounds great. Best I've heard.
It's a partial split.
Instead of turning one coil of the humbucker completely off, and leaving the other coil on as it is normally done, a resistor is used to leave part of the "off" coil still in the circuit.
Results in a "single coil sound" that has a stronger output and a fuller tone.