GreatHorn Mailbox Intelligence vs PhishingBox KillPhish: Side-by-Side Comparison (2026)

Short answer

Teams running Microsoft 365 or Google Workspace who need users to actually catch phishing will find GreatHorn Mailbox Intelligence worthwhile, because the visual sender indicators and on-click URL analysis force friction into the attack chain where it matters most. The tool scores across all three NIST Detect and Awareness categories, with particular strength in DE.CM continuous monitoring and real-time risk assessment that surfaces threats before the user opens them. Skip this if your organization has already deployed a mature endpoint detection layer and expects email security to handle lateral movement detection; GreatHorn prioritizes the user reporting loop and initial threat identification, not forensic analysis of compromise. Teams managing email risk across Microsoft 365 or Google Workspace who need their users to actually report threats should pick PhishingBox KillPhish, since the integrated reporting button plus live inbox training measurably shifts user behavior away from silent deletion. The vendor's Net Reporter Score directly tracks whether your workforce is becoming a reliable detection layer, which covers the PR.AT and DE.CM gaps most smaller security teams ignore. Skip this if you need advanced sandbox detonation or threat intelligence feeds; KillPhish is deliberately focused on making your users your first line of defense, not replacing your email gateway.

Based on our analysis of core features, integrations, company size fit, deployment model, here is our conclusion: