Which do you prefer parasound Halo a21 or McCormack dna1

There’s a DNA 1 with Steve’s Rev A Gold+ level revisions on EBay for $1749. I haven’t heard the A21, but the DNA amps with these revisions set a high bar and are an incredible value used. Best of luck.

I am very happy with my stock McCormack DNA 1. I saw the one for
$1,749 on ebay. If you're intersted,call Steve McCormack and run it
by him. I've spoken with him a couple times and he is friendly and 
enormously helpful.  No input on Parasound ,sorry.

a footnote......prices can vary on the McCormacks...I paid about 
$700 a couple years ago from TMR here on Agon. I'd say 7-8 hundred is a good ballpark price. If you can get a deluxe for that price,even better.