Like Matt, I do like the fact that you can choose to cut ARC off at the higher frequencies.
Matt, it sounds like the Anthem has higher pre-out gain than the Pioneer. This is an important factor that is often over-looked when buying separates. The pre-out signal level has to be matched with the external amp. If the level is too high, you may saturate the amp. If the level is too low, you'll never get full power out of the amp.
Judging by the engineers working there, I do think Anthem knows what they're doing.