Ultra means Ultra SCSI, and by context it means Ultra Narrow SCSI-2(50 pin), which can transfer data at 20MB/s over the narrow bus.
but Ultra SCSI is also SCSI-2 compatible, you just lost half of the bandwidth, which is still more then enough for the 12x burning job, in the case that you can not synchronize ultra SCSI (CDROM, old HD, Scanner).
Ultra Wide could transfer 40MB/s on the wide bus. (a plain wide SCSI-2 bus can transfer at 20MB/s)
Pretty much all the decent SCSI card supports ultra SCSI-2, and it depends on your need, do you plan to attach HDs later, and what type of configuration. Tekram make decent SCSI controllers if you don't
want to shell out more money for higher priced Adaptec.