Saying "dedicated servers are shit" is just neither here nor there and frankly sounds a bit ignorant to me.
I didn't say dedicated servers are shit; I said that the dedicated servers are often shit. I was specifically referring to the dedicated servers that I happen to have selected for me while playing Left 4 Dead.
It's certainly superior to have a machine dedicated to a game, but, for me at least, completely unnecessary in the case of Left 4 Dead, a mostly coop-based game that one tends to organize a group to play. For whatever reason the current matchmaking system for finding dedicated servers for a group doesn't seem to do a good job of selecting a server that pings decently to those in the lobby.
I don't know the specific upstream requirements per client, but I have no problem hosting 8 player VS games on business class cable, and we've had no issues whatsoever. I'm not saying your problems don't exist. I'm just saying that I've had no problems using listen servers, and consequently I'm going to tend to be "glowing about the game's multiplayer experience."