3 choices for power amp

Unfortunately I have not heard those amps personally however from what I've read I would go with the AGD Tempo or the AGD III Duet.

Here is one source of information:

Based on my experience, you are most likely to get the best sound quality by staying within brand.

I haven't heard your three choices but have an extremely good, modern class D stereo amp.

My Coda S5.5 stereo amp, for not that much more than the above, given a side by side comparison, would make anyone considering class D reconsider.

I believe there are others in the following link that feel the same way.

Coda S5.5 Class A Stereo Amp Thread

my recommendation is the same as vinyl valet stick with the amp within your family I think it'll probably sound the best.

I've owned the Benchmark and currently own the Atma-Sphere Class D.   I personally think they sound pretty different.   

I found the AHB2 to be extremely clean sounding, very solid bass, and highly resolving.   It had a super black background and you could hear into the recording like crazy.   I also found it to be a little lean sounding and 2 dimensional, not much front to back soundstage.   I liked it but at the time had a Pass X250.8 and preferred the big Pass amp.   The AtmaSphere has the super black background and solid bass, but sounds much more like the Pass to me.   I don't think it is as resolving as the AHB2 but it has more the color/tone of the Pass with better side to side and front to back imaging compared to the Benchmark.   To me, the AHB2 is a great tool to analyze a recording, where the Pass and AtmaSphere bring you closer to the music/soul of the recording.     My preamp is the SimAudio 740P (used on all 3 amps).   I would go with the AtmaSphere if you have the AtmaSphere preamp and am happy with the AtmaSphere sound signature.

Cheers

+1 @vinylvalet   The Coda is very special!

I know this sounds out in left field. Galleon A75. Down the road you will understand. 
At $1500 you are getting 95% of those including CODA but at 25% of the cost. 
good luck! 

@hsounds Have you auditioned the Coda S5.5 along with the Galleon A75 with your speakers in your room, level matched, etc? Or any Coda amp?

@hsounds Not sure why you answered the question privately as others in this thread may have the same question.

What exactly does "All I can say it has been tested per your question" mean? Which Coda amp(s)? By whom? Under what conditions?

That’s why. No trust. 

Nonsense, Shill.

Quite the opposite. It's folks like you that cause genuine enthusiasts to not trust these forums.

I believe I have helped a lot of people on and off this forum who have thousands of posts. I am a good problem solver so I like to help people out. This can be a frustrating hobby at times. I was just at a reviewers house who has been in the audio game a long time. They were having issues with their system. So much that they had not listened to their system since April before AXPONA. I was even yelled at by them telling me they did not invite me over to critique their system. I could tell they were unhappy. In the end I figured out about four different issues to improve the sound without spending more than $50. Two were free which we did right away. I’ve never seen sun body go from 100 to total happiness in 15 min. It bothers me when people are frustrated or down and out. Like I said this can get frustrating. It doesn’t matter who you are or how much money you have. I just like to help people be happy. I have no idea what’s going on in your life but I hope you come out ahead to where you can be happier.