There are three ways in which we differentiate from MVMC.

Supported Versions

MVMC is starting to show its age and hasn't been updated for quite some time.  It may or may not get a new version since it was part of the Solution Accelerator team which is no more.  MVMC does not support Windows Server 2012 R2 as either a guest or a Hyper-V host.  MVMC does not currently support VMM 2012 R2.  MVMC also does not support VMware versions past 5.0.  This limits both the systems that can be migrated from and where you can migrate the VMs to.  Our solution supports all of the latest technologies and also supports legacy back to Windows Server 2003 and ESX 4.1

Speed and downtime

MVMC requires that the VM be shut down and THEN moved over to the Hyper-V storage.  This means that the required downtime for a VM is significant because you are waiting for the large files to be moved over the network.  Our solution does a storage vMotion to move the running VM to Hyper-V storage.  We then remove the VMware tools, back up the network settings, and shutdown the VM.  We then immediately do the conversion on the same disk system. This gives a huge benefit of the speed of migration and have seen migrations of a 100 GB VM convert in less than 5 minutes.

Management and Orchestration

We've built a management structure into Xtreme VM Migrator to track the migration using a database and built our own integration pack in System Center Orchestrator to fully orchestrate the workflow of the migration.