Parasound A21+ or PS Audio S700 monos?


Since I have some time on my hands, I've been playing with my hifi.  And it's time for a new power amp.
Rest of system is an Exposure 3010S2 CD player feeding a Naim nDAC, an Exposure 3010S2 or Conrad-Johnson PF2L, speakers are Monitor Audio Gold GX300s. 

In looking and reading, it seems like the Parasound A21+ and PS Audio S700 are the leading contenders.  New S700 monos are $1798; a 1 year old A21+ is $2000.  

Thoughts on them?
naimfan
I have the S300 and like it but am interested how this turns out.  Might have to move up to the 700
Well, I have the Parasound A23 (obviously a model below the A21) and the stereo version of the M700 (the S300).  I find the S300 is superior in every regard - not in a really significant way, but clearly audible.  Cleaner and more articulate, the A23 sounds “thick” and less resolving in comparison.  
I’m guessing a similar difference would be heard between the A21 and the M700s. 
My $.02.  
Mine was in totally open air space. I purchased direct as a x dealer concession. It looked brand new. I sold it long ago