They're completely different. Note that most of the above scanners come with a SCSI interface. USB scanners are not sup ported by this backend by now.
Mustek scanners have no protection against exceeding the physical scan area height.
That is, if a scan is attempted with a height that exceeds the height of the scan surface, the scanner begins making loud noises and the scan mechanism may be damaged. This shouldn't happen if your scanner is in the list of known scanners. Please send all of it to the mailing list. You must be subscribed to sane-devel before you can send mail to the list. For SCSI scanners, the special device name must be a generic SCSI device or a symlink to such a device.