I have a real soft spot in my heart for SCSI. I'm one of those crazy PC people who tried to use it, paid the "tax", and didn't necessarily come out ahead for it.
SCSI is a beautiful example of abstraction and standardization getting is Cool Stuff decades later. While there certainly are edge cases and it's not as 'tidy' as I'm making it out, it's really neat to me that a device like the BlueSCSI[0] can come along and bring a healthy dose of modernity to old platforms.
SCSI is at a sweet spot of general purpose capability and abstraction from the hardware (unlike, say, the Shugart floppy interface, or even ATAPI/IDE) that allows devices to be built to just plug-in and provide significant functionality to legacy platforms.