I have owned the Merason DAC 1, Mk ll and even though it’s a fine sounding unit, the Aero is a significant step up. The best way I can describe the difference is the Merason puts you in front of a very good system and the Aero puts you at the live event. I also own the newest Linn DAC/streamer/preamp (a significant price difference) and the Aero DAC is right there sonically and in some ways does a few things better. Will I give up my Linn? Nope, but it’s great to have two wonderful sounding DAC’s at the same time. I do think the Linn has advantages as well, especially with their streamer and preamp built in.
I agree with teajay regarding price vs performance. The Aero is a home run for the price.