I replaced my Mac mini with a Node 2 in April of this year and I haven't look back since. The on-board DAC (Burr Brown PCM5122) sounds just fine if you want to stop there. I have the Schiit Bifrost Multibit and the Chord Qute EX to play around with and both of these DACs sound quite a bit better than the on-board DAC and they should considering all.
Bluesound Node2
Let me start by saying I'm a (very) late convert from vinyl into the digital domain. I finally got very curious about what I might be missing and recently purchased a Bluesound Node2 and got a Tidal HiFi subscription. I have it connected to my preamp's MP3 connection and I think the sound quality is real good, CD quality depending on the original content. That said, I see a lot of folks buying either external DACs or preamp's with a built in DAC. Given that I don't use my computer as a source for music, are there any advantages in having a DAC? I do have an average quality CD player that I occasionally use but I'm now finding myself using Tidal more and more for almost all my "digital" content. Just trying to find out what I'm missing. Thanks.