If your S3000 is the XL version you can use MESA or Millennium
I have 2pcs S3200XL and use both MESA and Millennium.
The big advantage of the S1100 OS v4.3 is that I can make programs on the S3200XL (with MESA or Millennium) and read them in the S1100 directly, so there is no need to connect the S1100 via SCSI to a PC and try to edit via SCSI.