There are two main problems with conventional Class D amplifiers.
The first being they have load dependant frequency response...for example, a B&O ICE module is designed for a 6 ohm load. When driving a 4 ohm load, the high frequencies are rolled off, when driving an 8 ohm load, the high frequencies rise.
The second problem is high voltage DC at the speaker outputs. If an amplifier uses a single supply of 100vDC, it will have +50v at both speaker terminals. This is a shock hazard and cannot be approved by UL.
You'll notice many manufactuers use Speakon or similar connectors instead of binding posts to get around this.
The D-100's frequency response is independant of the load, and uses a split rail power supply with no DC voltage at the speaker outputs.