There are a few restrictions
- If you are using Cluster Shared Volumes (CSV), Balance will not work. Customer use these sometimes in Windows Server 2008, but more so in Windows Server 2012.
- Balance ships as a VMware virtual appliance, and requires ESX to run. Some Hyper-V only shops deploy an instance of ESXi (free) to run Balance.
- Balance shipping as a Hyper-V appliance is on the roadmap, but will be at least a year out.