Bill,
As a PSB and Dynaudio dealer myself, I'll chime in. First, the Synchrony monitors sound wonderful and they are the best monitors they have ever made. But, they are no where near the league the Dynaudio C1 monitor is in. To be fair, there is over $5K price difference between the monitors as well.
I will say the Synchrony monitors require less current, so they mate well with a lot of different amplifiers. The C1's require gobbs of current for them to sing at low volume levels and to get the most out of the speakers.
I would suggest a better subwoofer be used than the 5i with the PSB Synchrony.
Hope that helps. Give me a shout if you want a more info.