I just wanted to put this out there in case someone else is having a similar issue.
I have two Dell R620 servers as two Hyper-V Cluster nodes.
Connected to Equalogic SAN
NIC Teaming enabled on Hyper-V Guest Network not shared with Host
Intel 10G 2P x520 Adapter
Intel Gigabit 4P x540/I350 rNDC
It seems there is an issue with VMQ being enabled, this was causing the VMMS service to hang/crash.
The symptoms were that all of the VM's were accessable, but when an action such as rebooting/starting vm guests, they would get stuck in the starting or stoping state. The only fix was to reboot the server, hard boot.
Disabling VMQ has resolved this.
I spoke with microsoft, they said its with the development team and they will be relasing a windows update to resolve this soon.