From the README:
This is the second of three planned betas in the 8.0.1 release cycle.
Most of the changes from BETA1 are bug fixes. In particular several bugs have been fixed in the migrations from 8.0-RELEASE. The system was not relabeling ZFS volumes to use the new devicename-independent naming scheme correctly in BETA1. Also the database migration scripts in BETA1 do not migrate NFS shares properly.
Changes since 8.0.1-BETA1:
The upgrade/migration scripts have been improved. In previous versions failure of the database upgrade was easy to miss, and it could leave the system booting to single user mode with error messages that had nothing to do with the root issue. This has been rectified. If a database migration does fail, the error message will be clear as to what happened, also the system will save diagnostic information that can be used by the developers to recover from the failed migration as well as make changes to prevent the issue from affecting users in the future.
iSCSI has been improved. The SCSI serial number can be set on a per target basis. This fixes an issue where MMIO was seeing different FreeNAS server as the same device. Multiple IPs can also be specified per portal.
The ssh daemon now logs to /var/log/auth.log
Several fixes have been incorporated into the volume import procedure.
Several fixes and improvements have been made to the remote replication process.
The system handles the timezone setting better.
CIFS now defaults to AIO enabled.