Playing Avengers feels like work. While it may have "flow," it's not as fast or exciting as the flow on Acdc.
Acdc provides a rush or thrill each time I play it. There is no other pin out there that provides the depth of strategy and "rolling the dice, and can lose it all" feeling that the song jackpot does on ACDC. There's also the thrill and pressure of trying to get, extend, and cash in on 2x/3x play field scoring.
But unless you're an A player, you're not going to see Encore. AV wizard modes, or at least mini wizard mode, is much easier to get to, but doesn't provide the thrill that skillfully planning and earning a 200+ M triple song jackpot during Album or Tour multiball does in Acdc.
Bottom line: there are MUCH better mode/quest based pins out there than Avengers. There is no better thrill-seeking high score topping, deep strategy scoring, non-linear pin out there than Acdc.