Bob,
It would be nice to see the industry moving towards a more flexible means of connecting these devices without having to charge a fortune for it. Seiko and the older Sapphire printers may use SCSI for transfer speed comparible to that of 100baseT ethernet. SCSI is nearing 320mb/sec transfer rate in the near future which is nice but I would hate to pay for cabling. Other than that, I would have to think they know the SCSI technology and have better resources, making SCSI a viable and cost effective solution for them. You know the saying, 'Stick with what you know'.
Ethernet is just so cost effective and functional. Most shops today have more than one computer, more than one version of output software and more than one output device. If not, they have one computer with 2 parallel devices, 2 or more USB devices, 1 serial device and then a network cable plugged into a DSL or Cable modem for internet. Sure would be nice, for the endusers that is, to be able to share these devices without the common problems of remote production managers, tripping over cables and such. Give each computer and output device an IP, run the cable properly (not lying on the floor or dangling from the back of a computer), hook them up to a network switch, and configure them in the software to communicate via TCP/IP. Then your output devices would be independent from an individual computer and you would avoid the issue of having to boot a computer to use a shared local printer.
The only problem I see with TCP/IP is upgrading firmware of the device itself. I am not aware of any means of upgrading firmware via TCP/IP. I am sure it will be here soon and yell at me if you know of any out there. Therefore a parallel or usb port would be needed in addition to the TCP/IP.
USB is nice but I hate loading drivers and making sure I am installing the device properly, whether the device should be plugged in before installing the software or after. Pain in the butt. Plus, have you looked for longer USB cables out there? I would rather buy a 50' patch 5 ethernet cable for $6.99 than buy 2 usb repeater cables for $16 or so each plus an extension at $15 to match the 50'.
You could always purchase a USB to ethernet adaptor as well if usb is the only option given by the manufacturer. There are several vinyl cutters coming soon with Ethernet built in... Can't wait for that.
Not to mention the ability to share between Mac and PC via TCP/IP. Maybe I am missing something but I do not like the concept of a USB port for a large output machine. Scanner, desktop printer, camera - sure.
Ethernet is the way to go.