Faster? I don't know, but I'm getting equal or better crushing from adobe, and great .jpg optimization as well - a 50% jpg saved from photoshop without the optimize function looks kinda yucky, whereas a 50% from ImageReady looks great. I used pngcrusher till I discovered that ImageReady (and this is like the last PPC only version of Photoshop/imageready, before mac came out with Intel Processors, so it runs under Rosetta) does a better job on both the file size and the quality of .png file.
Edit: also dropping an ImageReady processed .png on pngcrush does not usually result in a smaller file.
- Joel