AGD Duet owner here since last summer and they work great with the DeVore Super Nine speakers! I've owned a number of amps over the years and the Duets have brought out the best in the DeVore's. First time I have ever used mono blocks (due to space issues, etc.) which have made me a believer in that design. (Okay, and they are the most expensive amps I have ever used. :)
They are also compact in size, put out plenty of power and have both RCA andXLR inputs. I run my streamer/internet tuner directly into the RCA inputs of the amps, which allows me to bypass my tube based preamp, thereby saving tube life.
The clincher though is that the amps are upgradeable by the owner which will save time and money. While there are other fine GaNFET amps out there, AGD is the only company I am aware of that offers this feature which is important (to me) since the technology is still relatively young.