Comparison: AlwaysOn Vs Database Mirroring

	AlwaysOn	Database Mirroring
Reporting	Readable replicas allow real time reporting	The mirror database is always in a state of recovery, which essentially means it can’t be used while mirroring is active. You can create a snapshot of the mirror database to use for reporting, but the snapshot is a point-in-time copy making it unsuitable for real time reporting purposes
Read-only routing	Supports the re-routing of read-intent connection requests to a readable secondary replica.	This feature in not available in Database Mirroring.
Performance Considerations	Performing highly CPU, I/O-intensive read-only workloads on the secondary databases, it will improve the database performance of Source database.	Synchronous mirroring requires a 2-phase commit to take place which could introduce delays on the principal.
Additional H/W	Integrated with Windows Server Failover Clustering (WSFC)	Database mirroring doesn’t require WSFC but if you want to use it in High Safety mode for automatic failover, then you need to use a third SQL Server system as a witness.
Feature support	Only available with SQL Server Enterprise edition	Available with both SQL Server Enterprise and Standard edition. Synchronous mirroring is available only on Enterprise edition.
Risks	All active workloads must be licensed and requires additional cost of SQL server license.	Database Mirroring is available in SQL2012 and SQL2014 but will be deprecated in future SQL Server releases.
Schema or data changes	You cannot make schema or data changes on the secondary databases which limits creating additional indexes on secondary databases	The mirror database is always in a state of recovery, which essentially means it can’t be used while mirroring is active
Benefits	Provides High availability for SQL Server databases. Capacity of replicate databases to facilitate read only access which makes it possible for them to be used for multiple purposes at the same time. You can use a secondary database for reporting purposes.	Provides a high availability of the database and Do not need any singular hardware.