Yup! I got mine in January. I love it. To me it's sort of the neutral thick wide detailed R2R sound I love. I have it at my desk and it sound amazing on headphones. Some headphones sound better than others but that's the nature of great R2R dacs that aren't a billion dollars. Warm, thick, detail, great soundstage, all the good sound I want. It's great at the price point. Worth every penny.
I was curious to pull it into my speaker set up so I did. When I did this it sounded so good that I wanted to see what would happen if I used it as the preamp. I had the Schiit Kara. I did a lot of A/B testing using the R28NOS as only a dac going into the Kara and using the R28NOS as a preamp without the Kara and I heard zero difference. This is a great compliment to the R28NOS. Often times dac/headphone amps that have a preamp out have the preamp as an afterthought. In the R28NOS it is just as good as a great dedicated preamp. Just cautious and know that it only has XLR analog inputs if you want to do this, it does not have any RCA inputs. I took out the Shiit Kara and it sounded amazing. The R28NOS to me is one of the greatest values of hifi all in ones I have heard. Also, physical size wise, It's not as big as it's big brothers, the R27 models.
The sound to me connected to two Schiit Vidar2 monoblock amps is full wide and detailed. Just what I want for speakers. I forget I am listening to it which is my actual ideal. I like it when dacs and peamps sound so good like this does but doesn't have a sound signature intense enough that it constantly reminds me I am listening to it. I want my audio gear with my speakers to sound amazing but any one piece takes up too much attention, in the chain I find it hard to match them with anything. The R28NOS balances itself extremely well in the chain. I have Schiit amplifiers and Audio GD is known to work extremely well with Schiit products.
I ended up missing it at my computer so much that I found the R27RE used and have it in my speaker room and the R28NOS back in my office and I'm super happy.
For headphones I do not think it is a full on swiss army knife do all machine. It's close though. I do think the R28NOS is amazing as a pair or companion to a great delta sigma DAC. I have it on my desk next to a Geshelli Labs J2S 4499 dac and Archel3 pro, both fully loaded with the top of the like Sparkos Labs opamps. Its bright, sparkley, warm and detailed. Great to pair with the full deep warm enveloping detail of the R28NOS with headphones. For full sized headphones I am not going to be adding anyhitng else on my desk. This is my desktop endgame. In my headphone area I have an increduble dac I love connected to an Audio GD HE9 LE headphone amp. I am a huge fan of Audio GD. I think their price to performance value is incredible. The R28NOS is one of my favorite products I have heard from them.
I hope that is what you were looking for. I really think the R28NOS is a very special device and I HIGHLY recommned it. It's amazing as a partner to another amp and dac with a different sound signature.
Ask any other questions you need, no problem.