Anyone using J&S safeguard?

Im trying to see if this thing is worth getting. Everyone on the mazda forums recommended this device. I mentioned about using knock control on my megasquirt instead and pretty much got flamed for it. i just dont understand why i should dish out $6-700 for this when i can just rig something up with my megasquirt. It seems like a cool thing to have if you have a piggyback or fmu setup with no knock control. Can anyone tell me how this compaires to knock control in megasquirt or other stand alone systems other then “its just better”?

http://www.jandssafeguard.com/safeguard.html