I purchased 3 pairs (6 units) of SwitchBot Curtain 3 devices about two years ago.
Just before the 1-year warranty expired, one unit failed—the drive wheel lost torque and could no longer reliably move the curtain. Support replaced it under warranty.
Since then, two additional units have failed in the same way: one about a month ago, and another just last week. These are now out of warranty, so replacements would be at my expense.
At this failure rate (3 out of 6 units within ~2 years), I have serious concerns about long-term durability. These devices work well when new, but I would expect a product like this to last at least 5 years—ideally much longer.
Given my experience, I would hesitate to invest further unless reliability improves.