We all know that without decent internet connectivity that VoIP and all that comes with it won't be adopted. When I travel and have great bandwidth, with low latency, no packet loss and an absence of jitter, it's like the other party is in the same room.
On the other hand, unless you stand over the techs in the USA from the phone company or cable MSOs, often times you have to settle for something that is just good. Not great.
It seems over in the UK the results of some surveys and some testing proves out that one of the biggest hinderances to VoIP deployment has been shoddy line quality.