I bought a new USB floppy disk drive by Sabrent, which seems widely distributed among retailers. It mostly didn't work, and the exceptions were not enough for reliable service of any kind. No warranty was offered and the retailer's policy precluded a return. I ran it with Linux, although the documentation refers only to Windows and Macintosh. I contacted Sabrent about the symptoms and my attempts at usage and I expressed an interest in repairing the FDD hardware myself if they'd provide suggestions. Sabrent sent me a replacement unit at no cost. I like that. The old unit had Teac inside (viz., on boot the computer reported a Teac drive present); the replacement had Mitsumi inside. One nice detail is that both units' USB connectors had dust covers. However, although the Mitsumi was the replacement unit in this episode, it appears from the boxes' S/Ns and the presence of a paper about support inside one box that the Teac version is Sabrent's newer design (the FDD case S/N for Teac inside was 30844001510995 and for Mitsumi inside was 30609801503983). Both Sabrent models have the same model numbers (both are SBT-UFDB and both are FD 05PUB), all other numbers on the FDDs were the same, and Teac or Mitsumi is not mentioned on either the box or the FDD. But I doubt the Teac version is categorically defective; more likely my individual unit or some Teac units but not all of them were defective.
Apparently, the Sabrent drive is not meant to boot. It was first in my BIOS boot order but, according to the manual, the FDD is not supposed to get a disk inserted until at least a minute later. Inserting a write-protected floppy earlier led to freezing during the preboot process or during loading of the OS into RAM for booting, causing boot failure.
While a variety of retailers sell only Sabrent's model, Newegg sells several other brands but not Sabrent. I don't know enough beyond what Newegg's website says to compare the brands.