I've ran opnsense, untagle, and sophos xg on this little system. Sophos seems to run a little slow, the CPU sits around 20-30% consistently but I was able to max out my internet connection (500/500) and it didn't seem phased by my meager 15 clients throwing about  200-600 connections at it.Opnsense ran the best on it, very snappy. Had no issue with CPU even when maxing out my bandwidthUntagle ran very well, but I didn't feel like paying $50 to continue the service.Overall I'm very happy, I decided to stick with Sophos for the time being, even with it's UI sluggishness.