I’d purchased the MixPre 3 II without researching too much into it. It was the reviews of the microphone pre-amps that won me. When the MixPre arrived, it went straight to work doing voice overs. My reason for the saying purchase the MixPre 6 II over the 3 is that the MixPre 3 is limited in its inputs to the 3 XLRs. The stereo mini jack input has to be linked to a fader thus switching off one the XLRs. The MixPre 6 II would be a more flexible machine in field production while the MixPre 3 II, in my opinion, a bit too light weight.
Superb recording quality, steep learning curve for newbies
Challenging for a hobbyist to set up and use for maximal recording quality, but superb results when used with an external battery pack (though the USB stick backup seems to require more power than my Anker battery provides). There seems to be a quirk with the 32-bit recording when the levels are too high, where it seems to break down the waveform and amplify a parts of a quieter sections, leading to weirdly amplified ultra-high frequencies when reassembled to simple 2 channel. I suspect that keeping recording levels lower during initial recording will help avoid this, but have not yet tested it.