I thought I'd share my thoughts here on DSD, although I probably have longer "experience" with SACD rather than DSD as I've been buying SACDs since 2000. Back then it was buying SACD and their equivalent CD's and comparing on speaker systems. Comparing between the two was a hit 'n miss. Some like Dave Brubeck's Take Five it wasn't difficult to hear a difference between the two but some other SACD vs CD albums, it wasn't so obvious.
For DSD on the other hand, all my 24/192's come from the same SACD/DSD source (I'll leave it up to you to research how extraction is done). In that case, at least in my home iMac -> Invicta -> Stax I have to admit I find it hard pressed to hear a difference. I don't know if it's because 24/192 is truly indistinguishable from it's DSD source, or during the SACD -> DSD extraction that the DSD had degraded 'cos after all the extraction is done in a "DIY" setup rather than a professional studio. One thing to note though is that the 24/192 files I've downsampled/converted are even bigger than the original DSF/DFF files they came from.
As for a more generic thought on DSD, as I wrote in the NW-ZX1 thread, I wrote the following :-
Meanwhile about the topic of DSD, although I'm a huge DSD/SACD fan since 2000, I must say that it's not a necessity. It's definitely a nice to have & I even talked to some US vendors early last year to consider DSD support in their DAC Amps but it's not a must have. I've read in other forums where members who may not have experienced DSD shun a product cos it doesn't support DSD and I'm kinda disappointed to read that.
Note that DSD doesn't automatically mean better sound. To me, DSD just means it's closer to mastering. If mastering is bad, well you'll hear that bad mastering more easily or clearly. Also not all DSDs are from hires recordings. I've been told (although not substantiated yet) that there are times mastering is done at a lower quality (say 48kHz which is just above CD) to save storage space then later upsampled & converted to DSD format. Sadly I've not found an example of such a SACD yet. So personally I kinda trust old mastering instead - pre-digital days. If it's more modern digital mastering then Sony actually makes hires microphones for DSD mastering which I understand aren't commonly used yet.
IMHO, I actually don't think I'd expect to hear much diff between real-time converted DSD->PCM in the ZX1 vs a pre-converted DSD->hires PCM that's uploaded to the ZX1. This will depend on what the real time conversion is naturally. However, my pre-converted DSD->PCM 192/24 seem to result in bigger files than the original DSD files themselves!! So I welcome DSD support more to save space in my ZX1 instead.
I like to see DSD flourish in the audio world but I hope that it's more than just a buzzword and readers understand that DSD doesn't always mean "better".