Can't speak for this product yet, as I am yet to try it, but I can say, based off my experiences with John regarding the cMoyBB, a simple, cost effective amp that for me was comparable to amps many times it's cost, I have full faith in any new product JDS develops. It will be tremendously interesting to see how the impressions for the c421 pan out. I'm almost certain this amp will deliver in spades sonically and anticipate it to be among the best, for it's given price point, especially if the cMoyBB was anything to go by.
For anyone looking for ultimate value for money, go JDS. In the mean time, great to see John on top of things with respect to ironing out any minor teething issues along the way. If I hadn't spent so much on new amps/DAC's in recent times, I'd have already jumped all over this beauty.
looking forward to see if john will make a new product of amp and dac fusion