Really glad to see this review. I've been on the HTP-1 bandwagon for a while, now. Following along at the HTP-1 Owners thread over at that other site has been very interesting and informative. Seeing that some of your measurements agree with others not done by a former Microsoft VP, is also highly encouraging (it is seriously a shame that A.M. won't revisit that review and update it accordingly!).
Regardless, I've seen direct Monoprice and Dirac participation on that thread, updating important information and keeping tabs on bug reports. They have been super active in making the HTP-1 a fully functioning product, while you still see people complaining about and leaving the Emo ecosystem of Processors.
With the possible exception of Trinnov and Storm, no other similar super-processor is as functional as the HTP-1.
At this point, almost all bugs have been addressed. The main things left hanging are the implementation of DTS:X Pro and an answer to the Digital Board Upgrade for HDMI 2.1.
Issues that seem to crop up somewhat regularly is that there is no OSD, which some insist is a deal breaker for them, however the users report very consistently that they do not miss it and do not find this to be a problem worthy of comment. Also, there is no direct analog pathway: it is a digital processor and if you cannot live without analog, the users over at that other site will simply tell you that it is not the product you want. With that in mind, I have also never seen a single negative comment about audio performance leaving anybody wanting for that direct analog path, especially considering it would eliminate any of Dirac's corrections (which as mentioned, are excellent and not detrimental in any way to the enjoyment of any audio-only experience).
One last note of interest is that the Thread Starter of that Owners thread developed and made available his own custom UI. This has been commended by the Monoprice Project Leader that participates on that thread and everyone using it has raved about its functional improvement to the HTP-1 experience.
To see a company like Monoprice embrace such innovation and encourage it is just another example of how in-tune they are with the type of user this product was built for. At the same time, the non-power-users still rave about the control they have over the product and their systems, even if only using a fraction of what's capable.
Part of me is hoping ATI did not permanently shelve their own version, unless they saw that pushing the price tag significantly higher and further diluting the market didn't make sense. But if they stay involved in this partnership with Monoprice, I see only great things happening in the future of the HTP-1.
Thanks to the AH Team for this review!!!