I am a big fan of running everything virtually.  There used to be day when I had a ton of kit but now all I have is a small HP Microserver, an i7 Lenovo desktop PC, Lenovo T440S i7 Laptop and an i3 Surface Pro 3. I use VMware Workstation 10 as much as I can.   I used to use Virtual Box back in the day but found it just too troublesome with converting VM’s from manufacturers.
Most of the time it is very easy to download a virtual machine from a manufacturer and it will just run.  Juniper, Microsoft and some others are good.  Some will be in VMware appliance formats.  Others use the open OVA format.  Others such as Cisco, F5 and Fortinet will only support OVA’s that you can only import into ESX.  Workstations fails with various errors even though  – in theory – OVA is an open, portable format  …….
My fix is do this:

1) Download VMware ESX evaluation

2) Install as a VM within VMware Workstation

3) Navigate to the ESX Managment address via a browser.   Either use the Web GUI or vCentre GUI

4) Import the OVA into ESX

5) Once imported.   Navigate to the Data Store Browser.

6) Copy out the whole folder for the imported VM

7) Open the VMX in VMware Workstation.

8) Edit the NIC’s etc as nessiary

9) Start the VM

That seems to always work for me !