best approach for hyper-v infrastructure

Hi, 

We are managing an hyper-v infrastructure compose of 5 hyper-v physical hosts running Windows Server 2008 R2, this servers are in an active directory, but the virtual machines running on this hyper-v hosts are in different active directory, Is there any advantage running this platform in this way? I mean, considering issues like security, managing, etc, which is a better approach, keep it running as is, or consolide both Hyper-v hosts and virtual machines in a same Active directory domain? 

I would appreciate your opinions so much.

Greetings!