Great thread again!
I've had some PCM41/42 and 81 in various rigs for years; as much as the 80/81 are great powerful units that can do beautiful unique things, they don't "sound" like a 41/42.
Quick illustrative story:
I recently got a 41 again after foolishly selling my previous one 10+ years ago; as much as I love my 42s I've always regretted that particular 41 for some particular applications.
Anyway, I wanted to quickly check everything was working fine after unpacking that new one, so I plug my son's EMG loaded Charvel straight in, in front of his small JC-22 Roland combo; crank the PCM input level so that it flashes red as it should be; output level at noon; bring the volume up; "BAM", just a beautiful fat yet clear sound with great feel where the effect -whatever it is set at- just perfectly "blends in" with your main -improved- dry tone.
Decided to do a quick A/B test with the 81 I had next to it just to make sure I was not dreaming it, with the exact same setup: "it sounds too clean!!" (in Michael Thompson's voice & words

). Just a much thinner & clearer core tone.
The PCM81 can do some wonderful complex stuff and I love it with an EXP pedal for some particular special effects/parts, where the "clean Hi-Fi" character fits in.
But it just doesn't have the "sound" of the older 41/42, period. Even with Italo's nice presets

. The 41/42 also affect your core dry sound with their internal preamp and I/O analog stages, in a beautiful way. Feels like adding "good glue" to your sound. Just makes everything sound better just by running through them.