Not sure if you saw my post about the iBasso DX300, which is identical to the DX320 in every way other than the DAC chipset simply because they couldn’t get the chips in the 300 in quantity anymore. Also, while I haven’t had the opportunity to listen to the 320 compared to the 300, I have heard the 300 is slightly warmer (maybe).
At any rate, the reason I went with the iBasso to begin with is because the Amp is modular! You can swap the amp, and the Amp cards are the same for the DX300 and DX320. AND they have a NuTube Amp card!! My point is, I loved the idea that you can modify this DAP!
In addition, I was able to find a DX300 slightly used on eBay that had the stock Amp as well as the AMP12 module, which is a Class A amp module, and then I bought the AMP13 module that has the NuTube in it, so now I have a single DAP with 3 different Amps and slightly different sound signatures.
Again, keep in mind the DX300 has the same exact CPU, RAM, Display (wonderful), storage, and Amp modules as the DX320. The DX320 is $1,600 new, with the Amp modules being $200 and $250 respectively, and I was able to get my DX300 with all three Amp modules for just under $1,000!
In addition, the DX300/320 does work decently with ARC performance wise. ARC has no option to use SD cards currently (on the roadmap I believe) and they are planning to add DSP to ARC. For downloading with ARC, it can only access the 128GB of internal storage, but that gets you quite a lot of albums/tracks. Plus, you can stream over WiFi/HotSpot. I will mention, with the NuTube amp, the WiFi causes some noise… but I believe that is the nature of Tubes (maybe I’m wrong on that, but if you play local files with WiFi off it’s perfect). Another issue with ARC specifically (for now) is that it seems to upsample everything to 24/192, which is the max the DAC is capable of, but I personally don’t notice any sonic issues because of this. This only happens with ARC, and I think it simply is looking at the “default” the DAC reports or something. Also, not unique to this DAP… happens on my Sony DAP too.
Roon as an endpoint is streaming only, and I honestly haven’t messed with it.
Finally, you can add a 1TB SD card (up to 2TB once those cards come out) and I use that for a ton of music with the local Mango Music Player app, which is solid itself.
PS - On how my “used” DX300 looks, I honestly couldn’t see anything wrong with it! It’s as if it is brand new.