Well, if you've got a sophisticated network, then there's really no reason for you to have a voip adapter, with a built in router, in front of your router. I don't have a $400 router so I can put a cheap router in front of it. Not saying you have to have expensive equipment. You don't. But no two voip providers are identical. And there's no doubt that a certain combination of voip provider; internet provider; and home network works better than a different combination. And while you seemed to have had great success with Vonage, I've read plenty of reviews by customers who haven't had as good of luck using vonage.

I would definitely put the HT502 in bridge mode if you're going to use it ahead of your network router. (Just to get rid of the double-NAT). Even then, I'm not sure if you can get your bandwidth back. The HT502 specs says it has a 10mb/100mb ethernet port on it. But my experience is that it works at or defaults at 10mb. That could definitely stop your bandwidth. But you do have a lot of other options. It sounds like you know enough about networks, put the adapter behind your router and just use it for voip. If you do port range forwarding, you can set up all the ports you need in your network in less than 15 minutes.