The shifting is super quick and smooth, there’s no question about that. My problem with AXS is the ergonomics of the shifter. It goes up and down, this doesn’t really make sense in my head because up can mean two different things. Am I shifting up to a larger cog? Am I shifting up to a harder gear? Same thing with down, down to a smaller cog? Down to an easier gear? I’ve swapped the button configuration a few times and no matter what I do I miss shifts all the time because I have to stop and think about what “up”means on a rear cassette.
I have two bikes with electronic drivetrains, one Di2 and one AXS and the Di2 is way more customizable and the ergonomics make way more sense, left means you’re going to the left of the cassette (up to a bigger cog and down in difficulty) and right means right (down to a smaller cog and up in difficulty). It just makes more sense. That being said, I’d still rather have AXS than anything mechanical; but apples to apples, if I’m spending my money I’m going with Di2.