I bought a couple, they're really good, my only dislike is that the screen software is written as a Mopidy plugin, but I'd prefer a remote mopidy instance and the pis and hats are just clients with controls.
I assume this is only for the analog output, right?
Obviously if you're just using a cheap or old amp it won't have HDMI, but if you're amping with an A/V receiver you can just use the HDMI out and get perfectly good quality.
For snapclient, I used a USB DAC at first, but turning it off and then on meant that snapclient lost its connection. I could not resolve that so I purchased a DAC HAT instead.
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.