I have recently entered direct experience with Parasound amps. They are very very good. However, stock, they are definitely a tiny bit on the thin side and somewhat lacking in resolution (to my expectations). They are VERY refined and smooth, however. The problem with Parasound is that they fuse the heck out of everything inside.
The A21 as 5 fuses total:
1 x 15A main fuse
4 x 8A post transformer fuses
JC1s have 7 fuses total:
1 x 12A main fuse
2 x 12A post transformer amp fuse
2 x 1A post transformer driver board fuse
2 x 1A (small) post regulator driver board fuse
Once I upgraded everything to Furutech fuses (my standard), it really resolved the initial "lacking" characteristics.
I have read that the smaller A23 is not even in the same league as A21. Not sure about this. Could be the smaller power supply, but it still has at least 5 fuses.