It is possible that the preamps on these units may sound different, however all of the following will impact the sound and tone you get on a recording MUCH more than a preamp would.
1) Playing ability
2) Guitar used
3) Pickups
4) Amp
5) Cab
6) Mic used (SM57, Fathead, E906 etc)
7) Mic Placement (this can affect tone dramatically, the same mic on the same cab can sound drastically different depending on placement)
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So I wouldn't worry too much about specs, or "which unit is better."
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All three only have a single XLR input, you may want two for recording an amp, or you may not. I usually use 2 or more mics on an amp. Sometimes that is to "spread" two mics out, other times it is to have different tonal flavors available come mix time, when I find I by far favor the placement or tonality of a certain mic used.