SentinelOne vs Microsoft Defender when E5 already pays for an EDR agent

Microsoft 365 E5 lists at USD 60 per user per month and already includes Defender for Endpoint Plan 2, so every third-party EDR renewal now starts with the question of why pay twice. SentinelOne and Microsoft both sell EDR with automated response and cross-domain XDR. They split on the agent’s autonomy and on whether security rides the productivity license.

SentinelOne sells Singularity Complete and Commercial with the on-device Behavioral AI agent, Storyline correlation, and 1-click remediation and Windows rollback. Microsoft sells Defender for Endpoint Plan 1 and Plan 2 inside Microsoft 365 E3, E5, Business Premium, and the Defender Suite, with Defender XDR correlating endpoint, identity, email, and SaaS signals.

Buy SentinelOne when autonomous on-agent response with rollback must work across Windows, macOS, and Linux regardless of the productivity license. Buy Microsoft Defender when EDR and XDR should ride Microsoft 365 E5 or the Defender Suite the organization already pays for.

Overview

	SentinelOne	Microsoft Defender
Primary use case	Self-managed Singularity endpoint protection with autonomous prevention, Storyline investigation, remediation, rollback, and Purple AI, extending to cloud workload and identity on higher tiers	Defender for Endpoint EDR plus Defender XDR correlating endpoint, identity, email, and SaaS incidents in the Microsoft Defender portal
Day-to-day workflow	Work Storylines in the Singularity console, run remediation or rollback actions, automate with policies, and hunt with Purple AI	Triage combined incidents in the Defender portal, let automated investigation and attack disruption act, and hunt across 30 days of cross-product signals
Main buying consideration	Singularity Complete USD 179.99 and Commercial USD 229.99 per endpoint per year for 5 to 100 workstations through authorized partners. Enterprise is contact sales	Microsoft 365 E5 at USD 60 per user per month paid yearly includes Defender for Endpoint Plan 2 among other E5 products. Defender XDR is not a standalone offering. Up to 5 devices per user license; servers separate

We reviewed SentinelOne platform packages, Singularity Complete endpoint documentation including rollback and offline notes, and the EBlock customer story, plus Microsoft Defender pricing and FAQ, the Defender XDR overview and prerequisites, and the Defender for Endpoint service description, on 10 Oct 2026. We did not run either product in a paid tenant.

SentinelOne

Microsoft Defender

Editions and pricing

Both vendors print a dollar. SentinelOne prices per endpoint per year; Microsoft prices per user per month inside a broader suite, so the figures are not directly comparable.

	SentinelOne	Microsoft Defender
How it is sold	Singularity Core, Complete, Commercial, and Enterprise packages through authorized partners, with Vigilance MDR as a separate managed tier	Defender for Endpoint Plan 1 in E3, Plan 2 in E5 and the Defender Suite add-on to E3, Defender for Business in Business Premium, and standalone plans
Figure on the public page	USD 179.99 per endpoint per year for Complete and USD 229.99 for Commercial, 5 to 100 workstations	USD 60 per user per month paid yearly for Microsoft 365 E5. No Defender Suite dollar printed on the Defender pricing page
What the unit counts	Endpoints, with cloud workload protection listed on Complete and ITDR from Commercial	Users, with up to 5 devices per Defender for Endpoint user license. Servers licensed per operating system environment

Agent detection and response

Both sell EDR with automated containment. The split is where the decision runs: on the device or in the cloud service.

	SentinelOne	Microsoft Defender
Detection object	On-device Behavioral AI kills or quarantines without cloud connectivity, and Storyline correlates process context	Next-generation protection, attack surface reduction rules, and cloud-delivered EDR detections with automated investigation on Plan 2
Remediation	1-click remediation on Windows and macOS and 1-click rollback on Windows, without re-imaging	Automated investigation and remediation on Plan 2, plus live response sessions on devices
Operating systems	Unified Singularity agent for Windows, macOS, and Linux, with SaaS, on-premises, hybrid, and air-gapped deployment documented	Windows, macOS, Linux, Android, and iOS clients, managed from the Microsoft Defender portal

XDR scope and identity

Both extend beyond the endpoint. The documented split is a platform tier ladder versus suite licensing that switches on XDR when multiple Defender workloads run.

	SentinelOne	Microsoft Defender
Cross-domain object	Singularity platform tiers add cloud workload protection on Complete and ITDR on Commercial, with Singularity Data Lake retention	Defender XDR auto-enables when multiple Defender workloads are licensed, combining endpoint, Office 365, Identity, and Cloud Apps signals
Automatic disruption	Autonomous response on the agent and policy automation in the console	Automatic attack disruption requires Defender for Endpoint Plan 2 with Identity, Cloud Apps, and Office 365 Plan 2 or suites including them
AI analyst	Purple AI for natural-language hunting and summaries on Complete	Security Copilot integration in the Defender portal, listed among E5 highlights

Favor SentinelOne when the documented requirement is offline on-device Behavioral AI, Storyline, 1-click remediation and Windows rollback, and per-endpoint Complete or Commercial pricing across operating systems. Favor Microsoft Defender when the documented requirement is Defender for Endpoint Plan 2 and Defender XDR attack disruption already licensed through Microsoft 365 E5 or the Defender Suite.