if you do end up using a superhub then follow Masque's advice, its upto you if you want to disable the whole firewalll or jus the ip flood, my self am running with firewall on as in test i did i saw no diffrence
http://www.cableforum.co.uk/board/35244823-post5.html
on the netgear front i only have experiences of dg834g v4's on adsl, but i do remember that the upnp on it caused some issues when the xbox was turned off and on in short period of time and would not connect to live un till i logged into router and cleared the upnp map