So, I replaced my Radar II/Motu 2408/PCI424 with an Apogee Symphony system. I'm a die hard mac guy and have been using Performer for more than 20 years.
Installation of the Symphony system was incredibly easy.
I compared the conversion of the Apogee units to my Radar (classic converters), my CraneSong HEDD192, and a MOTU 1296. I felt the Apogee a/d was right there with the HEDD, which is the best a/d converter I own. The Radar lacked midrange detail and the 1296 lacked midrange period.
The d/a side was harder. The HEDD sounded better than any other option. The Radar "clasic" converters sound great to me. Absolutely soft on the top end in a way that's pleasant. The Apogee d/a's (and to some degree the 1296) have the open top end of the HEDD, but don't have the same low midrange, bloom or reality (your choice) of the Radar or the HEDD. I could see using either the RADAR or the Apogee da16x depending on the project. I mix analog, so converter sound "pile up" is definitely an issue. No clear d/a multi-track winner for me.
All this digital listening was done with all gear clocked to an Isochrone, and checked out via my hand-made (ooh!) passive monitor switcher and attenuator.