Thanks for the note. I've waited for this kind of Mac OS X native app for a long time.
Some quick observations:
I was stunned that it could draw a graph from a hours long DVD in only a few seconds. I was prepared for a much longer session. Where does it get the bitrate info so fast?
I then tried to open a "loose" .mpg file but it seems to only open an authored DVD. Could it be updated so that it could open also .mpg, .m2v and m1v files?
What about an ability to zoom into the graph so that one could evaluate it by the second? This would be useful when evaluating whether some blocky scenes get the bitrate they deserve.
It seemed to open only the first track of a DVD that iDVD 5 had burned.