I just moved to the area and prolog seems very similiar to optimum online which I used before moving here.
I'm aslo running a vonage phone on it and service is good.
I use p2p all the time without problems, limewire and bittorent.
I'm using the modem they gave me, SA webstar. It's okay, had to reboot a couple of times but other than that seems okay.
It's only been a couple of weeks, but so far so good.
Wish I could help with some of the other techniacal questions but not my area, I don't even know what a vpn is lol.