I’d describe the difference more in the overall presence of the sound - A&H mixers have, in general, a lower noise floor, a “bigger” presence (due largely to even wider bandwidth internally, and again, lower noise floors), and a “warmer” or “more musical” EQ than Mackies, which have an EQ more suited for live sound (audibility and thud are more the focus of Mackie’s mid and bass ranges, instead of more musical timbre control in the case of A&H). On the not-really-audible side, A&H tend to have fewer mechanical issues over time (you don’t hear this until the mixer ages, but then you don’t hear it, which is the point!), and more durable construction (even the Zed series, if I recall correctly, has vertically aligned mixer cards which keep dust and debris out of the fader track). Also I think their power supplies are higher quality and present less injected noise too. Mackies are excellent budget, compact mixers for FoH duties or other live reinforcement purposes and they’ll work in a small studio in a pinch, but they are not really what I’d consider studio grade gear if you’re looking to increase your signal chain quality across the board to a more professional level of expectations. A&H definitely are, though of course the sky is the limit (look at the stuff coming out of folk’s SSL consoles, etc).
