I'm pretty much done with my recent hifi upgrades, and so far I'm very happy with the results. I've got Topping DX3 Pro DAC/preamp/headphone amp going into my old active Genelec speakers, and massdrop Sennheiser HD58X headphones. Raspberry Pi running spotifyd is connected to DAC via USB, optical from TV, which still leaves two coaxial inputs unused (+ bluetooth). The DAC is tiny and inexpensive, and supposedly the measurable performance is quite decent.
To my ears everything sounds good, I like the simplicity and small size (previously I've used preamp part from a massive late '70s integrated amp) and I can use Android Spotify app as a remote for the Raspberry Pi. Using Raspberry Pi also means I could try dabbling with room correction at some point. What I can't easily do is hook up the record player, but I don't see this as a massive negative at the moment. Maybe I'll do a retro setup in the basement at some point :-)