It was really bad when launched, but to call it really bad now (or in 2018) is not fair. A lot of poeple waste their money on these hats when they don't need to.
Has the hardware improved or just software? I have a DAC-Hat and it definitely picks up some sort of digital noise from the pi. I can literally hear SSH when large amounts of text are being dumped across the wire.
The Pi 1 B+ was improved with a dedicated power supply and I think that might have been it on the hardware side. The big improvement came with the software, details of which are linked elsewhere in this thread.
