I am currently doing an evaluation of VOIP vs current PBX(or upgrading) for a client and I've run into a stumbling block. While I have found plenty of info on the plus side of VOIP as well as security risks that could be a negative does anyone have specific information on performance problems with VOIP? I really need a both sides of the issue evaluation but aside from vague references to voice quality i can find nothing specific-can anyone help??