On the send end for my "playback" DAW I have an older Lynx One where I just use the AES out (which goes up to 24bit/96kHz). What I like about this is that the sample rate of the card locks to whatever I set my DAW to - so if I have a session where I've received tracks at many different sample rates it's no hassle to have the whole digital output chain (SAWStudio -> Lynx One -> ZSys 8.8 router -> Lavry Blue DAC) lock to the sample rate set just once at the DAW. It also has MIDI i/o on board which is useful to me as I hook my CM Motor Mix to it so I can control the playback DAW's transport and fader even when I have my "capture" DAW displayed on the screens they share via KVM. I see them on ebay for about $250 or so - and as such they offer good bang for buck. If you don't have a regular need to output at 192kHz (and to date no one has ever supplied me with 192kHz session files) then it's still a good workhorse for the mastering studio imho.
For my "capture" DAW I use the SSL/Sydec Mixtreme 192 which is capable of 16 channels digital i/o via 2 TDIF cables. I have this tied to a (now discontinued) Apogee Soundscape 896i/o which has 8 channels each of AES/TDIF/ADAT digital i/o, as well as still decent sounding Apogee AD & DA. While I usually just send via AES to this from my Mytek Stereo 96ADC, if I need to do an 8-channel transfer I can do it, and use a couple of the channels of DA to send to a pair of meters as well. The Mixtreme is capable of very low latencies, and has really nice virtual routing options allowing you to easily send audio streams from one application to another without having to connect real cables as well, so it comes handy for my rare production chores as well.
Obviously both of these cards are on the end of their support life spans and are not representative of the "latest and greaters" - but since they both work great for my needs, and have well developed solid drivers, I have no plans to change them for something else currently. I've been using the Lynx One for 6 years now, and the Mixtreme 192 for 5.
Best regards,
Steve Berson