What is your upstream? I've found that is usually the killer for me. If I'm talking on voipo and presenting a Webex session they are both using up my upstream. What happens is I would hear my clients just fine, but they said I would get fuzzy or my presentation would take a while to change on their end. If you have 256kbps upstream and plan to talk and do anything else that may involve uploading you may get fuzzy. I had to upgrade to Time Warner's turbo road runner for that reason. If you just talk then you will probably be fine.