Full disclosure, I am a McIntosh dealer.
Now that that's out of the way; I did just install a C53 in to my system yesterday. It replaces a C48 which obviously has similar levels of functionality. I've generally enjoyed the performance of the C48 and from an integration standpoint, it worked flawlessly. But, I would say that the DAC in the 48, while perfectly good and flexible, left some performance on the table.
I'm also an NAD dealer and have a C658 in the system. This gives me access to BlueOS and also full MQA which McIntosh does not support. In my opinion, the DAC in the C658 outperformed the one in the C48 in most respects. Apples to apples, the C658 was a little more relaxed, warmer and with a bigger bottom end. Generally a little more engaging to listen to. With MQA files, I noticed improved depth and dimension of sound stage through the NAD, a hallmark of the new medium, for those who believe in it.
I've sold and tested many lines of product over the years. Some including very expensive DACs, stand-alone and integrated. And I would have to say that it's rare that I've been genuinely impressed. Sure, there are certainly differences but when taking in to account the ratio of dollars spent vs. potential performance gains, I've found myself less "moved" by improvements, DAC to DAC than other components. I even emailed Ron C at McIntosh to get his impressions of the C48 vs. C53 as a result of my skepticism.
Enter the C53 and DA2. Even cold and with no run-in time, I was surprised to be able to hear distinct differences. Right out of the box, the DA2 is generally better than the DAC in the C48 which shouldn't be a huge surprised. However, I was intrigued enough to also want to do some A to B comparisons with the C658 and this is where I was more surprised. For everything not MQA, I think I already prefer the DA2 to the C658. I now find the C658 to sound a little "dark" and the bass a bit slow and round through the NAD in comparison to the DA2. Neither DAC sounds overtly "digital" in any negative ways but the DA2 , in my mind, takes another step toward some of the illusive analog qualities most find appealing. Mid-range texture sticks out to me. With certain recordings, this is quite noticeable and pleasant to listen to. Bass is well balanced and tuneful, not one-note-ish, but musical. And the top end has more air than either the C48 or NAD. Pace and timing is also very good. I don't know if I would yet say that the DA2 has the dimensional qualities of the NAD with MQA files, but depth of field with the new C53 is definitely better than the C48. This could be largely attributable to the line stage as well.
For reference, the rest of the system consists of a McIntosh MC462 amplifier, Rega RP10 turntable with Apheta 2 cartridge (I haven't done the comparison between the MC preamps in the 53 and 48 yet), Sonus Faber Electa Amator III speakers and REL S510 sub cabled with Audience AU24SX (power, balanced analog, digital audio and speaker) and an Audience Adept Response power conditioner. Digital sources are NAD C648 BlueOS and Sonos Port and the system is integrated with Control4.
So, I personally do think that the DA2 is a good DAC and solid all-around performer. I also think that this generation of McIntosh preamp and amp combinations are a noticeable step up from the previous.