I've just given Endian a quick spin in a Virtualbox test environment. Looks very good and has some nice features free out of the box.
Looks like it will be easier to configure for blacklisting/whitelisting domains than ClearOS and I like the authentication options (including AD.) Think I will try it in the live environment sometime soon.
Don't try in live environment until you've tested extensively.
AD authentication may sound awesome, but it has it's drawbacks. 300 000 http requests via the proxy in an 8 hour period, and each one of those waits for an authentication packet from the domain controller.
1. User sends request to proxy.
2. Proxy sends auth request to DC.
3. DC sends reply to proxy.
4. Proxy then sends request to cache.
5. If cache misses, then sends request to outside server.
6. Data returns to proxy.
7. Proxy delivers to user.
8. Proxy caches.
9. Repeat for next file.
Steps 2 and 3 can cause quite a bit of delay, which we found out the hard way. It's just extra packets on your network, and it does bulk up the HTTP headers a bit. But for some it is a necessary evil.
The one downside we've had to the EFW has been the actual firewall. Being an iptables nut, I prefer to hand code it, and the logic that EFW uses isn't alway clear. So blocking torrents etc has proven to be a PITA.
Other than that, we love it.