Pros: Excellent clarity, imaging, efficiency and very high quality (handmade in the USA).
Cons: Could use a little more bass.
The Heresy III is an improvement over the Heresy II, which I also have a pair of. the quality of construction is excellent and the clarity and tonal balance is excellent at all volume levels.
The Heresy III is pretty efficient at 99 db 1 watt/1 meter, more efficient than anything in it's price class or close to it's class, including the Klipsch RF series. the imaging is excellent. I wish they had a little more bass below 58hz, but that's the way it is, they are crisp and clear throughout most of the listening spectrum.
The HIII on paper is an absolutely phenomenal beast, now they are available on the Klipsch web site, at the price, they are a bargain, as my HII's are almost 25 years old and still sound better than many speakers costing much more. The Heresy III at $1500 a pair are expensive, but how many speakers live in a pristine state for 20+ years. My mother has a pair of 1962 Klipschorns, and they still sound better than anything else on the market, granted at their current $3750 each, they are not within all budgets, but as with all Klipsch products, you get what you pay for, excellence.
I own both RF series (RF-52's/RC-52), Heresy II's and Heresy III's and love them all
Klipsch is the oldest and largest American speaker company, at $750 each, the Heresy III is not for everyone, but for those that appreciate cinema quality. I have owned a pair Heresy's for over 20 years, they sound as good as the day I bought them. My GF loves the RF/RC system. All of the Klipsch Heritage line (Klipschorn, La Scala, Cornwall and Heresy) are hand made in Hope, AR, this kind of quality does not come cheap and is worth every penny.