The DA8 does indeed have a linear power supply with a large toroidal transformer and fairly extensive voltage regulation, etc. I've also got the LPS-1 and if you open it up you'll see the guts look very similar to what's found in the DA8. It's just that the DA8 has it all in one enclosure rather than a separate section.
The DA8 uses an asynchronous USB implementation. It's quite good - USB input sounds better than SPDIF to my ears, unless I use a super-duper transport like the Audiophilleo AP1 with PurePower. I'd say the built-in USB is probably better than your NuForce 192S.
I've heard the DP1 on several occasions and I liked it. I never had it next to the DA8 to directly compare though. I hear a lot of similarities, based on memory alone. Both are somewhat on the warmer side with a very well controlled top end, meaning no harshness or digital glare. I honestly don't recall anything from the Eximus that would blow away the DA8 except for the fancy casework. In fact, the Yulong may be the better DAC. Especially over SPDIF as I feel the Eximus has some bottlenecks due to certain design choices. The DA8 definitely has the better headphone amp section though. I didn't care for the one in the DP1.
Thanks for the answer, Project86.
I'm surprised to hear that USB sounds better than SPDIF as a general rule SPDIF is always better that USB. Or maybe in DA8 SPDIF input just very average and not on a par with USB?