Is it normal for a second U1 to cost less than a multi-color Bambu setup?

Running two U1s side by side here. I queue them separately rather than splitting a single job across both. Splitting one print across two machines is more trouble than it's worth since each machine runs its own slicing and you'd have to align the halves, match settings, and hope both finish at the same time. What actually works better is treating them like two workers on a shift. Slice a batch of parts, send half to one and half to the other, and start both. If one finishes early I just load the next job on it while the other keeps going. That's how you eat into the wasted capacity, not by splitting a file.

The one exception is if I'm doing multiples of the same part. Then both machines run the identical file and I just let them churn. Two machines on the same 4 color job will beat one fancy machine on throughput every time, as long as the job fits in 4 colors. More than 4 and the two machine setup doesn't help you at all.

For the filament mixup, I stopped trying to remember. I got a pack of colored vinyl tape and put a strip on the spool, a strip on the tube end near the coupler, and a strip on the shelf slot where that spool lives. Red tape on red filament, white tape on white. Sounds dumb but when you're swapping at 11 at night it saves you. I also unload a spool completly back into its bag with the desiccant when a job ends, so nothing sits half loaded on a machine getting confused with the other unit's stock.

One more thing, check your power draw before running both flat out at once. My bench circuit runs both fine but the lights dim for a second when both beds heat up togehter, so I stagger the starts by a couple minutes. Not a problem, just a habit now.

Been running a pair of machines in the garage for a few years now, and the garage dust is the thing that got me before the filament confusion ever did. Petals and sawdust drift in no matter what, and a jam halfway through a long multicolor run is a real mood killer. I keep both under cheap plastic covers when idle and blow the feed paths out with canned air before a big job. Learned that habit the hard way back when I was babysitting a single extruder and swapping spools by hand at 2am. Do you notice much temp swing in the garage overnight, or is yours a conditioned space?

Same here on queuing separately, that's the only way it's made sense for me too. The thing that helped most was sorting the batch by print time before sending jobs out, so each machine gets roughly the same workload and neither sits idle waiting on the other. I keep a cheap dry-erase board taped to the bench and jot down which unit has which color loaded before I walk away. Wiping it and rewriting takes ten seconds and I stopped grabbing the wrong tube entirely.

Following this with interest since I'm not even at two machines yet, still running my one U1 next to an old single-color printer I had from before. Reading this makes me wonder if I shoud just save up for a second U1 instead of upgrading the old one. Question for those running a pair: does the slicing software let you send jobs to both from one computer, or are you walking over with a stick each time? That part is the bit I can't picture. Also the tape idea is going straight into my notes, I lose track of which spool is which with just one machine alredy, so I'd be hopeless with two.

The other upside of buying a second identical unit that I never see factored into these comparisons is that everything is interchangeable. One spare nozzle, one spare hub, one set of spare belts covers both machines, and a profile that prints clean on one prints clean on the other because they are the same machine down to the same firmware version. I keep mine updated the same week so the slicer profiles never drift between units. One question on your math though, did your total include the filament dry boxes and the extra shelving, because mine somehow doubled once I counted everything around the printers rather than just the printers themselves.