I don't have any actual evidence, but I suspect a V3 at 24bit/48 that is absolutely dialed in running as hot as possible without clipping *might sound better than a MixPre II in 32bf/48, exported to 24/48.
But would the end result be THAT much better? idk.
'better' in out application? probably 'different'. but if you looking at a preamp as what comes in goes out, on a distortion basis
mixpre: 0.005% max (@1 kHz, 22-22 kHz BW, gain=20 dB, -10 dBu in)
that translates to about -86dB of harmonic distortion, with a relatively hot -10dBu input bumped to +10dBu
we dont really have a spec on mixpre in a high gain situation
V3 is 0.0011% (-99dB of harmonic distortion) gaining 40dB from -20dBU to +20 dBU
V3 is 0.0046% (-87dB) at an impressive 60dB gain from -40 to +20
some of the top-of-the-line preamps like a benchmark MPA1, are 0.0002 to 0.0004% (-108 to -112dB) in THD+N
but some people prefer distortion in their sound (transformer pres. etc)
and thats not to say the mixpre AD stage isnt optimized for a lower input level.
for the separate component preamp the goal is to try to get the signal as hot as possible to maximize the capabilities of the ADC
remember that the EIN of all these components are pretty fixed around -130dB. low level signals will always be at a disadvantage which can be overcome to an extent by putting a sensitive cap on a mic with high output (like a 4006 on an MMP-A)
in our application (micing PA in a room with a dynamic range of like 60 dB at best), all of this is relatively academic, and features win. As far as simplicity im pretty sur ei could go into any venue and set the V3 at 25dB of gain and walk out with a good recording (indistinguishable from a 32-bit recording) with levels peaking between -25 and -8 dBFS.