To answer your question about the Lynx,
Yes it is a significant difference in sound quality!
Believe me, I have a Motu 828Mk2, and I use the thing as a HIGH PASS FILTER!! If you ask me, converters should not sound like cold, brittle, lifeless caca!!!!!
The Aurora has got to be one of the most accurate, true to the source A/D D/A's out there. What other professional device offers 16 AD and DA in one RU rack space! The Lynx setup would be a great way to get professional sounding conversion at a really great price point.
Just pair the Aurora 16 with an AES 16 for complete integration into your software.
To my ears, the Lynx series PCI cards and converters, do not impart any coloration or tonal change in your audio. The Lynx has really clear, present and extremely detailed frequency response.
The Aurora will allow you to really "hear" your tracks. If you have a more accurate converter, you can focus your microphones better, as there will be no "sound" from the conversion. You will be able to better judge the tone of your microphones and line signals going to "tape".
The same can be said for the Apogee series converters. In my honest opinion, the AD and DA 16x's are the cream of the crop as far as professional AD DA conversion. The Apogee AD/DA 16x's have the most amazing musical texture that certainly complements many types of music, such as rock, R&B, pop, hip-hop, smooth jazz, etc..etc..
The Apogee has a really "BIG" bottom end with a smooth, rich midrange and top end. I have also found that when clocking the Lynx from the Apogee Big Ben master clock, the depth of stereo field is increased and the bottom becomes tighter and just as "BIG" as the apogee can be. Something to think about.
I think either way, the addition of the ATB will allow all the versatility and professional results you are after.
peace
mixwell