@Jerry1098
I have XG105 rev. 3 and using it as ESXi host for networking tests.
The CPU doesn't have power management features that you'd find on a regular PC, so it's only useful as a network device.
Consider that Sophos has a free firewall and VPN, even if your license has expired.
That model was designed as a VPN device for SOHO and homeworkers, so it seems like it would be fine for other VPN installations.