This image is 1.5MB. Webkit and Trident—that is, 75% of the browser market—cannot render any more than the first frame, which is only about 11KB worth of data. There are 274 frames in this image, and the vast majority of users can only see the first one.
This file is 645KB, less than half the size—because there are lots of good tools that can optimize GIFs. It works in every single major browser. It has the same amount of color information—contrary to popular belief, GIF is only limited to 256 colors per frame, not per image. The framerate is wonky because, well, I have no way to tell what it should be: there are barely any tools for working with APNGs. The best I could do was dump all the frames and stitch them back together at an arbitrary constant framerate.
APNG was invented because Mozilla needed animations with translucency for Firefox's UI. That's all. It's not a recommended standard. It's not the wave of the future. It was rejected by the PNG group. Nobody has any reason to implement it, especially when there was already a format that does the same thing.
If you want to use something nobody can see as a push for support, you could always jump on MNG! At least Konqueror can render those, I think.