I do not have any experience with the 27AC but I do have a fair amt of experience with Synthesis gear. I recently upgraded from the A40 integrated amp, incredible sound with a fantastic DAC, to the Synthesis Roma 98DC mono blocks and the Roma 117DC preamp. The quality and build of Synthesis gear is top notch. I will probably purchase another A40 for the family room system as my wife does not want multiple boxes and the sound was sublime, I have Audio Note speakers which love tubes.
There is one currently for sale at USAudiomart that is local to me, I would not be surprised if he bought it at DejaVu Audio in McLean, VA. I would give VU and the guys at DejaVu a call to see what they have in trade-ins, I would imagine that the A40 I traded in is still available but it is significantly more than the 27AC. They are a wealth of knowledge when it comes to Synthesis gear. I hope I was able to help.
John