I do my development in a virtual machine running in VMWare and I was initially a bit confused on how to setup Genymotion up in this scenario.
Decided to share my setup, in case others would like to do the same.
Install Genymotion on host (bad idea installing it within another virtual machine)
Genymotion will setup a host-only NAT
Open VMWare's Virtual Network Editor, and create a bridge to the Virtual Box's Host-Only Adapter
Create a new network card in the virtual machine and map it to the vmnet that is bridging to virtual box's host-only adapter
When adroid emulator is running, start the Genymotion app and note the ip address
Run the adp (on the development machine) connect to ip address noted in previous step. I have scripted this as shown below:
And you will see the emulator listed in the xamarin studio (in the virtual machine); clean & simple.