I actually might need some help with that. For me this is all new. And above, I am comparing what I actually used. Yes the RX-V663 was old, but that is what I had to compare the new MRX-740 to. And I don't use stereo. I actually have the AVR set up to push all 7 speakers including use of a 7 channel stereo setup. This new MRX-740 AVR just sets up automatically. I was having problems with my RX-V663 as I could no longer stand and try to figure out the old not updateable firmware. If the newer stuff was any different, and I had distinct descriptions worth considering of improvements in the Yamaha new lineup I obviously did not get it here.
I did get from my local dealer demonstrations of various setups including Yamaha, and I just liked the feature set and capabilities of the Anthem with ARC better. All reviews I saw ranked the room correction as YPAO<Audessy<Dirac<ARC<Trinnov with Trinnov being the best, and YPAO and Audessy close to the bottom. What I understand is that Dirac and ARC is somewhat closer, but the ARC seems to win out with most of the reviews that I saw that compared the two. The low ranking of YPAO and my experiences with the RX-V663 version of YPAO soured me on considering a new Yamaha unit no matter what AcuDefTech guy said. As I have stated my Sound United objections above I won't repeat here. But Anthem seemed to both review well as far as audio output, as well as the ARC combination. The ARCAM stuff was also good but I think it uses Dirac and was twice the expense of Anthem for a similar feature set. If money had been no object, I would have gone with Bryston/Trinnov for amplifier and processor combination. Since I am on a budget, I had to make a compromise that fit within that. So I went with Anthem. This here lays out how I made my decision. Since it is done now, if someone likes something better, I don't begrudge them that. But with all the posts here, this is what I came to as a set of conclusions. It is healthy to debate, but hopefully this helps explain what I saw and how I came to the decision I did. Anthem like any human made component always can and will have flaws. How a company supports after the sale makes for me a big part of the consideration as to why I choose a product. For me Anthem fits all of the criteria and the compromises I have had to make. My original budget with some wiggle room was around $3K that I had mentioned in another thread.
If you are going to use REW to plot the actual FR graphs then I am sure many of us here will be able to help. Regarding comparison with Yamaha and/or others, I understood you could only compare it with what you have/had. Again, my previous comments were made to highlight the fact that your comparison was made using an much older and lower model of one brand vs a newest mid model that someone new to this hobby may miss. I did not mean to contradict any of what you said at all.
As far as YPAO<Audessy<Dirac<ARC<Trinnov with Trinnov being the best, I think you would likely agree that such online reviews need to be taken with a grain of salts because there are just too many variables and subjectivity involved. It would be nice if Harman would do a follow up comparison tests that they had done years ago. One of the reasons Audyssey was near the bottom in most online reviews is that few (yes there are some) were using XT32, and almost none if not in fact none were using the Editor App. With the Editor app, I was able to (others too such as Pogre, Jon AA) were able to get a flat 20 to 125 or higher Hz range response, like within +/- less than 1 to 2 dB, and then from there it is hard to slope it up towards the low end to suit the individual's taste. No doubt AARC is one of the best REQ system out there but I think the gap between the top 3 have narrowed to the point it may not be all that different audibly speaking, if the EQ freq is limited to the room transition frequency. Trinnov is not that affordable to a lot of people, so that one is a mystery to me and I think because it is pricey so people naturally will think it is among the best, if not the best.
As an aside, AARC (Anthem's), like YPAO is IIR based, it is inherently not as good as FIR (Audyssey), and the hybrid (Dirac), but that's just in general, and both have pros and cons. Obviously Anthem's has been highly rated by even the objective experts, and I hope their latest version (likely in the MRX740) has been improved further, and that's why I really look forward to some feedback from you, who seem to be the first on this forum to become a proud owner.
There is really only so much it/REQ can do, so like distortions in amps, it will, if not yet, get to the point that they (the top 3,4,5) that the major brands would adopt will be so effective that there won't be all that different (audibly) any more.