Just got to Chaos In Quantum City for the second time. This time I paid more attention to the mode. Man, what a rush! The light show is great, and I was in the zone, just hitting ramp after ramp. At some point, I looked up to check my score, and drained in the process. Reminded me of the Kenny Rogers song: "You never count your money while you're sittin' at the table / There'll be time enough for countin' when the dealing's done".
I do wish they would add a MB or wizard mode that allowed you to actually complete an objective. I love the Battle the Wicked Witch wizard mode in WOZ, for instance. It is so tough, but when you melt the witch, it is a great feeling, and you are awarded with a 5 ball victory MB. Of course, in WOZ there really aren't modes like in DI, so perhaps that evens things out.