A first batch of HM-602s was released to the Chinese market only sometime early September. Using feedback from this batch, Head-Direct had made some further modifications and tuning to the final design, which is the version that is distributed to the US and other markets, including China I presume from now on. It sounds like whatever feedback you're referring to was from that early batch. I have posted a preview in mid August about my impressions of that at Can Fest, NC and the sound quality of that pre-production sample was not bad, but nowhere near as good as the final products. I think I said something unscientific as "80" of the HM-801 or similar to illustrate my impressions.
The final version's overall sound quality, at least thru headphones and IEMs is different now to that of the HM-801 (depending on which amp module the 801 is using), but that "difference" has narrowed considerably. So the choice between them could indeed depend on factors like budget, preferred genre and application (on-the-go or desktop listening) than tiering based on specs vs the flagship model.
Bear in mind this is just my evaluation based on my hearing. Others may come to a different conclusion and prefer one over the other.