The email quarantine process is as old as email itself, and still an essential part of any email service. As far as Office 365 is concerned, Exchange Online is a world-class product and the quarantine mechanism works well, however, the current iteration of the Quarantine portal falls short in user experience and performance.
Steve Goodman writes on how you can use Authentication Policies in Exchange Online for blocking Basic Authentication in your Exchange Online tenant.
Microsoft has improved the phishing and impersonation detection capabilities of Exchange Online Protection and Office 365 Advanced Threat Protection with anti-phishing policies.
As Microsoft invests in development of the Security and Compliance Center, some inconsistencies and annoyances have crept in to Exchange Online Protection administration.
A curious case of legitimate Azure Active Directory Identity Protection weekly digest emails being quarantined by Exchange Online Protection when international spam filtering is enabled.