As you can see, I have used this quite a bit in the last week. It was designed by George Smart M1GEO after he accidentally cooked his Wellbrook active loop!
Overall, it works very well, but I wonder if it is less good with weak signals on the higher HF bands. Mostly, EU stations are copied, but where the RX noise figure dominates, maybe it is less effective?
See https://www.george-smart.co.uk/projects/wellgood_loop/ .