Anyone else find the Core One+ slower to dial in than expected, or is that just me?

I run an MK4S and picked up the Core One a few months back, and honestly my tops came out rougher too at first, then I found the problem was the table. Mine sits on an old wooden desk that rocks when the bed slams back and forth. I put a thick rubber mat under the feet, leveled them properly, and the top layers cleaned right up. Wasted an evening chasing slicer settings when it was furniture the whole time. Check that before you buy a better table, a mat might sort it for a few dollars. As for comparing the two machines directly, side by side same filament, I'd say the Core One edges out the MK4S on top surfaces now that it's sitting solid. The enclosed frame prolly helps with some materials too. PETG on the open printer always had a slight sheen difference for me.

On the multi-material side I'm with you. I kept my MMU3 on the MK4S for a year and the purge tower drove me nuts on longer jobs. The swap speed difference alone got me printing multi-color parts I used to skip because I couldn't stomach sitting thru it. Still keep the MK4S for quick single color stuff though, it's nice not having to think about wich tool is loaded. That balance works well for me and I've stopped comparing them directly. They do diferent jobs in my little print corner.

I went through the same head scratching last winter with mine, and I ended up in a different place than the furniture theory. My Core One sits on a proper workbench in the garage, dead level on a concrete slab, and I still had that slightly rough top surface you describe. What actually helped was two things in the slicer. Turning on ironing for the top layers made a bigger difference than anything else, and I slowed the top infill speed down to about half of what the profile ships with. Between those two changes my tops went from slightly pebbly to honestly as nice as anything my old MK4S produced. So my take is that the extra mass moving around and the toolchanger going back and forth does shake things a bit more than a bed slinger, but the surface finish itself is mostly a profile starting point, not a hardware penalty. Try the slicer tweaks before you buy a new table.

On the purge waste question I am firmly on the multi-tool side. I print a lot of functional parts in two colors, things like mounting brackets and adapter plates, and the swap speed means I actually use multi-material now instead of dreading it. A friend kept his single nozzle setup and swears by manual filament swaps for his use case, so it really depends what you print. For anything with more than three color changes I whould never go back.

Been printing since the days of painter's tape and hand-leveled beds, so a slightly rough top barely registers to me anymore. One thing I'd try before blaming the machine is drying your filament. Rough tops on PLA were almost always damp spool territory back on my MK2, and it's still true now. A few hours in a food dehydrator fixed it then, fixes it now. Also, don't sweat the six evenings. My first MMU1 assembly took two weekends and a fair bit of strong language, and it jammed if you looked at it wrong. What you've got is luxury by comparison. How's the filament feed path looking on yours, any grinding near the spools?

One thing I'd add is that mine got noticeably worse tops after I moved it across the room, and a full calibration pass fixed it, so if you do relocate the printer to a heavier table, rerun the whole setup routine afterwards rather than assuming the factory numbers still hold. I've also found that slowing the top layer speed down a notch does more for surface finish than almost any other tweak, and since the whole appeal of this machine is running faster, it's easy to forget the top surfaces are where that speed shows up first. My multi-color jobs still finish quicker overall even with that slowdown, for what it matters.

Update: took the advice and did the whole checklist. Moved it onto a heavier table, added a rubber mat under the feet, reran the full calibration like one of you said, and the wobble is gone. Tops are better but still not quite where I want them, so now I'm blaming the filament like the damp spool theory suggests. Sticking a spool in the dryer tonight. How long do you all usually leave PLA in there before giving up on it?