We've had a lot of success with pfSense. BGP works, IPSEC works, most things work quite well with no headaches. My previous employer used a Watchguard firewall and to be honest pfSense was a much better experience all around.
Except for cloud VOIP. Neither 8x8 nor Shoretel worked worth a darn through this firewall. We even paid for the gold support and opened more than one support case with no luck. It appeared to be a RTSP issue, SIP didn't have any trouble. And it was intermittent. Most of the time it would work, occasionally it would not. Eventually we replaced pfSense with a Cisco router for our phones and it worked fine.
Except for cloud VOIP. Neither 8x8 nor Shoretel worked worth a darn through this firewall. We even paid for the gold support and opened more than one support case with no luck. It appeared to be a RTSP issue, SIP didn't have any trouble. And it was intermittent. Most of the time it would work, occasionally it would not. Eventually we replaced pfSense with a Cisco router for our phones and it worked fine.