Look you lot ...
Here are some facts of life - bandwidth costs ! I know that might be a surprise to some of you, but the ISPs pay REAL money for their bandwidth - real money, not just some loose change from down the back of the sofa !
If you really, really want to have 8Mbps available all day, every day, then you CAN have it - but you won't want to pay for it ! Seriously, you will NOT want to pay for it. Think what you pay for your residential service now, and shift the decimal point a place or two to the right.
Now, assuming that you've picked yourself up off the floor after finding out what a real "unlimited" service would cost, now think about how you actually get your service for what you do pay. The facts are quite simple, the ISP relies on diversity - not everyone will use all the bandwidth all the time. This worked fine for a few years when the bulk of the traffic was of an intermittent nature - but then along came P2P which allows people to use lots of bandwidth for lots of the time.
Unfortunately, here in the UK (don't know about the US), a sizable part of the ISP community decided to paint themselves into a corner by competing on how cheap they could be. The result now is that they have lowered the expectation of cost to the point where it's not possible to provide the service people are expecting at a price they are expecting to pay.
Also unfortunately, may of the same ISPs have decided to simply try and hide the facts - in effect they tell porkies, like anyone in possession of the facts would believe you can have "unlimited" traffic for a tenner a month !
The result is fairly predictable - the ISP don't have the capacity to handle the users traffic carrying expectations, and they don't have the cash to upgrade because they've screwed themselves down on price.
So ANY ISP with intentions of running a half decent service will HAVE to employ some level of traffic shaping. They prioritise the traffic so that a) no one user can hog all the bandwidth, and b) certain types of bulk traffic (ie P2P) can't make other traffic unusable. There are three types of ISP when you consider this :
1) The ones who are open about it (not many)
2) The ones that do it but claim they don't (most, liers !)
3) The ones that don't so it and their service is crap - forget about using VoIP or any delay/packet loss sensitive application) on anything run by these cowboys.
The comment from an ISP employee sounds very much like my ISP - definitely in group 1 above, and guess what, the service is fine ! P2P works any time of the day, but is slower at peak times. Even when they are dropping millions of packets/s, VoIP and browsing are fine.
Yes I really did write "dropping millions of packets/s" - because that's what ALL ISPs do at peak times. Most won't admit it, but they have a finite bandwidth down a pipe, finite buffers in the routers, and so some packets get dropped. That's a fact of life unless you are all prepared to pay AT LEAST ten times what you pay now for bandwidth.
So for those that said comments to the effect of "I'd like to know which ISP so I can avoid them" - well if you want to go and buy a worse service AND be lied to, then go ahead !
Having said all that, what Comcast appear to be doing is totally inexcusable. It's one thing to buffer traffic (and drop packets when the buffer overflows), it's something altogether different to fake packets to drop connections.