[Freeswitch-users] Is QoS needed / beneficial?

We currently plug our CentOS 5.x FreeSWITCH server directly into our service provider's ADTRAN to connect with the outside world, and to a switch for intranet (of which a 2nd firewall is connected there and to the ADTRAN for our other servers). We are shopping for other providers who are shocked that we don't have a router in between that is doing QoS to prioritize the voice/SIP traffic. Is a router w/ QoS capabilities a good idea? Thanks, Jason