Avnx
The Bond aircraft had EGPWS Mk XXII v26 In that version the suspend button behaves just like the one for AVAD - it suspends the "check height" generated by going below the pilot-set radalt bug, but does not affect the "100" call. The EGPWS audio inhibit button inhibits all audio warnings for 5 minutes, except the "check height" and "100" which are unaffected. Its true that there is an on/off switch for the whole system, therefore its slightly easier to turn the whole system off than for AVAD, where it was necessary to pull the circuit breaker.
Although there is filtering to prevent nuisance warnings when measured rate of change of radalt is >5000'/min, this is the same as for AVAD. The radalt data is otherwise used directly to trigger the mode 6 "check height" and "100" callouts, without further processing or algorithms. However as you say, complex does not necessarily mean better and it is perhaps true that the EGPWS is a complex box full of software and therefore could be considered less reliable than a straight AVAD, but otherwise it is a fair replication of the functionality of AVAD.
Therefore I consider that the EGPWS does comply fully with JAR-OPS 3.660, but it is complex thus affecting pilot's understanding of how it works as well as reliability and probably its effectiveness offshore.
HC