Pros: Very expansive frequency response. Amazing musicality combined with an extremely detailed presentation, paradoxical yet achieved.
Cons: NA. Maybe too much bass for some people.
As the other reviews have covered most of the 8A's sound signature related qualities, I want to focus on its outstanding merits which I believe to be unique only to the 8A.
The sound signature is supremely rich and musical yet Heir have managed to allow the 8A to portray incredibly high levels of detail. I would assume this is somewhat paradoxical, and would be seemingly impossible to achieve. Yet, the magicians at Heir have managed more than accomplish this 'seemingly impossible feat'.
In addition, a rich and musical sound signature is correlated with a poor soundstage. This is not the case for the 8A. The 8A has an amazing impressive soundstage that is very expansive and spacious. Listening to Mahler's 8th symphony aka the symphony of a thousand, it feels as if I am inside a hugh concert hall and can pinpoint the entry and location of every instrument with ease.
The 8A has extremely powerful bass that will literally send vibrations through your torso and above. But this is not to say that it is lacklustre in the other frequency ranges. In fact it can go endlessly low as well as endlessly high without any loss of control or depreciation in sound quality. Listening to lossless recordings of violin duets, I am thoroughly impressed at how clear and beautifully presented the treble range is on the 8A as well as how effortlessly it can produce the higher pitches and still maintain timbre and not sound harsh.
As powerful as the bass is, it never overwhelms. I never expected it but the 8A is an absolute delight to listen to classical recordings of chamber orchestras, duets, quarters, quintets and so on. Last but not least, the 8A truly shines when it comes to reproducing large scale romantic orchestral works. Very difficult to describe in words, but it is truly astonishing. All embracing, holistic and supremely warm yet detailed and expansive are the words that constantly come to mind.
You can see from my profile that I own a lot of high end audio gear. This is because my father is an audio maniac. In our basement resides the Focal Grande Utopia EM. What is amazing is that I rank the 8A alongside the Utopia as my favourite audio gears.
The isolation has a lower rating as nothing beats my Shure olive tips!
And last but not least. The aesthetic qualities of the 8A is well.... Need I say more? Have a look at some of Wizard's works!