In college (Berklee), I was a dual major - MP&E and Music Synthesis (now something like Music Technology). The LM3204 was in the better labs (L1, L2, etc.), and it sounded fine, and by that, I mean it didn't sound like anything. IIRC, these were made in the USA, and at the time, Mackie was a reasonably new company coming out with some revolutionary products (8 buss, Ultramix, etc.).
If I needed a line mixer, that would be the one that I would look for. Otari made a fabulous line mixer, but I've only seen a couple pop up over the last ten or twenty years.