What's different? Per Jeff:

"I've tweaked this to squeeze as much speed out of the Apache as I can without giving up too much usable memory. This means that while I've decreased the size of various file system caches, I've increased the size of the PagePool from 6MB to 8MB. I've reorganized the Start Menu to give you quick access to everything with minimal clutter. I've cut out unnecessary files from several OEMs and system modules to decrease the overall size of the ROM and the number of files jammed into \Windows. I've integrated many of the new HTC applications and utilities and tweaked them to work together as cleanly as possible. I've automatically unlocked the now blank Ext_ROM partition and moved your Temporary Internet Files there to keep them out of your main storage. I've unified the overall look of the user interface as much as possible. And I've preconfigured just about everything with different default settings so you can just flash, sync and go. This kitchen builds the ROM your carrier should have given you."

Again, per Jeff, (You will) have the fastest, cleanest and easiest Apache out there and can outperform a brand new HTC Mogul