Even though I actually haven't ridden that way since they built the cycle track, I live in the neighborhood and the cycle track has looked awkward to me since they put it in. Back when I commuted home down Beacon I would bomb down the slight downhill to the Star Market at 25 or so, pretty far out into the "car" lane, because I wanted to be able to see, and have time to react to, any cars attempting to pull out of the side streets.
To the grandparent's point, the cycle track is really only compatible with laid back putt-putting. I think if you were to carry any speed at all, you'd eventually get T-boned by a car pulling out of the many poor-visibility side streets ... or you'd T-bone the car yourself ... with your face.
So if I'm out on a ride (not just going to the store or something) I think I'll avoid the expensive new cycletrack, thank you.