The straight field mixers (442, 552) are older products and have a few features that are useful for production sound work. Those mixers were usually paired with SD recorders, but production mixers have mostly moved to the 600/800 mixer/recorders and in some cases, the MixPres. For most field recording and studio applications, I think the MixPre’s are superior products with improved preamps, mixing, multichannel recording, and audio interface functions. I’ve used my MixPre 6 for all my live performances to mix and send audio to the house system. My next step will be adding a MixPre 10 II, so I can have my field recording kit with the 6 always packed and ready to go, with the 10 II cabled up in the studio.