The cdi from Dynatek is the same CDI used on the Brute 650/750 with a harness on it. You can get a programable one too. They have just not put them together yet in a package.
You an expect the same performance gain as the Brute 750 gets with the dynatek box.
As far as which one outruns which I doubt there is enough difference to matter, too many other variables.
Our first shipment is due in Tuesday if anyone is interested and we will be selling them for $199.95 including shipping and I know you can buy them on ebay for $172 but we are doubling the warranty to two years and those guys don't have the money invested we do, they just sell a product out of some hole in the wall for a quick profit. We fully support what we sell!!