I've done a few of them for customers. The machining seems top notch and The use of O-rings over diaphragms is cool, but in the end it's still a BOV.

As far as I'm concerned, if you're running a ball bearing turbo or one with a 360 degree thrust washer, you don't need a BOV. If you do run one, just have it recirculated and you will avoid these problems.

Whether you have a BOV or not, you're still snapping the throttle shut and cutting off your air between shifts (making it run rich).