Those guys were at NERAC II (North East Reef Aquarium Conference - Long Island, NY) a few weeks ago, and they had a demo tank set up with an out of the box MaxiJet 1200, a maxijet modded with their kit and a Tunze (I dont know which but I can probably find out).
They were inviting people to do the unscientific "feel for yourself" test, sticking your hand in front of each in the tank. In my opinion, their modded maxi-jet *significantly* outperfomed the original maxijet as well as the Tunze. I was very impressed by it's performance.
That said, I personally wouldnt spend that much on something I could make myself. However, if you arent big into DIY, then thats another story.