One issue that Microsoft ATP users have is with configurations—or misconfigurations. For example, as discussed on this Reddit thread, even when users set, by policy, to send spam detections to be quarantined, it instead gets "Filtered as Spam" and sent to the Junk folder. This happens despite the policy being set to do the opposite:
One possible reason is due to misconfiguration. See how one of the policies is to quarantine the message; another is to move the message to the Junk:
Avanan catches the targeted attacks that ATP misses. Because of that, we can limit our false-positive rates, meaning your protection is broader and more effective. That means your users won't have to deal with Dumpster Diving in the junk folder. By preventing malicious emails from ever reaching the inbox, your organization will be safer—and admins will be a whole lot less frustrated.