I've been looking forward to this book/chapter/what-have-you since John Wick offered a tease of it on his blog. Most omni-systems leave me cold because game A does something cool that game B cannot really replicate. Attempting to shoehorn all these systems into one generic system just mostly sucks (Savage Worlds may be an exception for me).
The difference with this product is twofold (1) it lets you keep your original rules to each game you want to utilize and (2) it lets you pull a truly great trick on your players. This is a small product (arounnd 20 pages), but well worth its cost.
If you're sitting on twenty plus years of gaming books like I am and worried you'll never play them all, The Flux has seriously offered some help towards shaking the dust off them.