The problem for Topping (and others like SMSL) is they have a scatter brain approach to marketing/manufacturing DAC's (i.e. they give birth to a new DAC every 2nd week or so it seems).
To be successful with PEQ/DSP you need to invest in a PLATFORM that can reach across a small set of components that are released in a logical and methodical manner, over time.
Take DEQX, DSPeaker or MiniDSP or more recently Wiim as examples (although in Wiim's case, compared to the other three, the longevity of their platform is yet to be seen).
These companies recognize that you just cant knock up DSP/PEQ in a short time so if you want to be successful you need a long term vision, base you efforts on a platform (off the shelf like SHARC or custom) that is extensible and will stand the test of time.
Topping et al, in my opinion, dont have that vision or patience... its all about chasing the next model cause they believe product churn is where it's at.
On a side note, one issue I see with Topping is their fetish with small form factor components. Which is why, for example, you get the D10S and D10B. Any normal company with a logical marketing dept would produce ONE model with both RCA and XLR analogue outputs in a case that supports this... but no... we need two models and because our case is so small we need to use pro audio TRS balanced connections just to make it that much more messy and harder to integrate into a consumer audio customer base (noting MiniDSP is also guilty of this with some models only using TRS)
Sure Topping has models that do support RCA and XLR but in their mind, they will sell more stuff if they shove out a DAC with only one or the other cause they can sell this for $200 bucks cheaper than a combo model.... which to me is false economy, both from a design effort perspective and a manufacturing/tooling effort.
Peter