Sarcher,
Rereading your original post you stated that you are currently using the A21. Stepping up to the JC-1's is a huge jump in output and control. The A21 has 250W and 60 amps peak per channel. The JC-1 has 400W and 135 amps peak per channel. Also, I didn't see if the A21 had an independent power supply or not but if it doesn't, there is another excellent advantage for drive tough loads.
I don't think you can go wrong with the parasounds. There are so many owners driving their systems with the JC-1's. "50 million people can't be wrong" :-)
The resale value is really strong on these amps so worse case is you pick up a pair, evaluate them and decide to resell. You may eat shipping costs but you will certainly get your investment back. A small price to pay to audition one of the most respected choices for SS amplification for electrostat owners.
Good luck and let us know what you choose.