It is not just "good", it is perhaps the best thing money can buy in a case where one is satisfied with the features of the product. I have been using it for a while now and it is flawless - not only it allows for a proper subwoofer integration due to high-pass filter, but it also needs less power (smaller power supply, runs significantly cooler with 32V compared to 48V) when the high-pass filter is used as supposed. Not only the above mentioned Aiyima does not offer this feature, but it is also twice the price. Even if it was the same price, I'll still go for the Douk A5 - to me the subwoofer integration is more important than the difference in the (not-so-holy grail as marketed) PFFB.