I took the time to explore the Endian UTM that I came across on the interwebs.
This UTM is a good choice for the home user it comes with the standard tools like CLAMAV and SNORT its a light weight UTM.
As with most LINUX based UTM’S such as Untangle and Sophos you will need to allocate a dedicated machine or use a VM.
The installation is simple and the web interface is easy to use. The specs needed are also reasonable they even included NTOP directly on the UTM which offers great visibility into the network.
Again this solution is not for a business as it doesn’t meet some of the business needs but this would be a great UTM for the home.
They do however provide a business edition with all of the needed business features.
Check out their site at http://www.endian.com/