I do t think we can classify either one as being chassis grounding or signal grounding . They can both be connected either to the chassis or to a signal related post . So to say the Tripoint is only chassis grounding and Entreq signal grounding , is not entirely correct. The larger Olympus does have a centre peg that connects to the power grid , with cable of choice . They do however have different energy release characteristics from a Listening perspective . Back to the Select ....
Entreq devices are floating "sinks", the Tripoint Troy uses the ground path of a mains cable in an high impedance mode, RogerD uses an extremely low resistance classical ground star scheme. IMHO these are the main differences. The choice of chassis or signal ground will also depend probably on the internal grounding characteristics of equipment.