We're using the DX168/X to connect to an Allen & Heath SQ5. Physically, it's quite small - smaller than I expected and there is a rack mount accessory for mounting into a 19" rack. The setup was really simple, connect the SQ5 (or other compatible mixer) to the DX168/X using a Cat5/6 cable with ethercon connectors. Connect power to the DX168/X and turn on. Go into the IO screen and then select SLink - from here you can assign the inputs or outputs to channels.
The quality is great as you'd expect from Allen & Heath and I don't see any con. The only thing to worth noting is if you chain this with some of the older generation 48KHz accessories, the DX168/X will also run at 48KHz instead of 96KHz. In this situation a SLink expansion card is probably the way to go so you don't reduce the quality of the DX168/X.