A thing I have uncovered about T1 should alleviate any misconceptions most people have about it and its "blazing" speed (go for oc149... then you'll know speed *drool* .... gonna have to hunt down some new NICs though :angel: ).
Most people believe that T1 is a lot faster than cable, not true.
Cable has higher throughput (transfer speed of data), probably due to attenuation or something similar.
T1 has higher bandwidth, so allows for more information to be transfered without a slowdown in throughput...
So technically, T1 is better for a network, as it allows for more information at a cost of speed... which ultimately is better since the loss in speed isnt dramatic.
Also, as Mr. Wizard said, you'll never get max bandwidth (if im not mistaken it should be throughput... bandwidth is just the amount of data that can be sent... not the speed at which it can be...)
Each individual networking device (hub, bridge, switch, router) adds latency to your network (at the cost of reliability) increasing from hub to router (if I remember, a router can take up to a 20% toll on your network alone if it has a network specific configuration)
So if you lost me anywhere, throw in quick lamens.
T1 = More data, Cable = Data faster