I use the Blitz SBC-iD .. VERY NICE !!
Easy to use .. and easy to learn how to use ..
Boost holding wise .. very stable .. fluctuates 0.01 bar and never taper off till redline ..

The only thing I don't like is the auto mode .. hence I run manual mode

The boost response is alot quicker compared to the stock valve

 

This would confirm what I remember reading about the Blitz unit.
Basically made more power, faster...

The HKS is the only company to still stick with the stepper motor...not sure why, since it is slower and less precise.