Unison Research S6 or Leben CS-300F or Manley Stingray II???

Hello fellow audiogoners. 
I at a loss choosing between the three.
The only amp I have been able to audition in my system is UR. Sweet, nice, too loud for my taste (volume at 10AM was already too loud) ,  but lacking in openness and soundstage . 
Leben is said to be very nice and sweet and stuff, but it lacks remote controls, which is a downside in my case.
Manley Stingray, in my opinion, is very nice looking, and fits the bill in all aspects, except Stereophile treated it like an entry-level amp, lightly and condescendingly, if you know what I mean. It also rated the Stingray II as B class, while the other two were rated A.

I would very much appreciate comment from those of you who have had the opportunity to audition all three (or at least two of the contestants ).  My main question here is about the sound character and differences of these three amps rather than functionality.

Listening to the other two is not an option, unfortunately.

Source is CHORD DAC64, speakers are open-baffle speakers of local manufacture, rated at 93dB and 4 ohms. They are currently powered by a Hegel H300, but it sounds a little dull and uninvolving. 

Thanks for your opinions. 

Andrey