My advice is not to let these formats drive your choice of receiver. There are many other more important factors to consider in selecting a receiver
The Denon 1082 (3802) does DTS ES byt not DD EX.That is incorrect. The 3802 does indeed decode DD EX.
Dolby Digital decoding, including Matrix 6.1 decodingThis spec means Dolby Digital EX.
I am not sure,but I believe that the H/K 520/320 only had DTS-ES processing and only DD 5.1But those models also had Logic7 for 5.1 sources, which effectively gets you DD EX (better, in fact). My guess is that Harman didn't want to pay an additional licensing fee to THX and Dolby for use of the EX trademark. (They own Logic7 through their ownership of Lexicon.)
It's important to remember what we're talking about here. DD EX is simply DD 5.1 with some additional matrix processing applied to the left and rear surrounds, so that a center surround is extracted. DTS-ES Matrix is exactly the same thing (so much so that DTS initially paid Dolby a license fee for it). If a receiver has the ability to extract one or more additional rear channels from the left and right surrounds of a DD 5.1 mix, then the receiver "does" DD EX, regardless of how it's labeled.
But those models also had Logic7 for 5.1 sources, which effectively gets you DD EX (better, in fact).This part is incorrect. The HK 320 and 520 have Logic 7, but it only works with 2 channel sources, not 5.1 digital sources. I believe the HK 8000 does use Logic 7 with 5.1 sources.
On my HK 320 you can get 6.1 and 7.1 in the following modes:
DTS-ES (digital 6 channel source)
with 2 channel sources...
7 channel stereo
Dolby Digital is only 5.1 and Dolby PL II is also only 5.1
Also remember with the HK 320 and 520, you'll need a another amp to run the surround back left and right speakers to get 7.1. The newer HK 325 and 525 have 7 amps built in and does DD-EX as well as DTS-ES.