Yeah - although we discovered that the better the controller microcode was at handling errors, the better life was for the user, disk vendor, and system manufacturer. On the VAX, the SI controller was not extremely forgiving and I had left that world. I wonder if some of the super eagle's issues were that the controller did not gracefully handle drive errors. IIRC Emulex's SMI and Unibus controllers tended to be smarter than SI's. FWIW: Once Xylogic did the 45x series for the Multibus/later VME with the microcode solid and Unix drivers got written to handle the errors returned, my experiences were ( as Larry said ) we had few problems with any of the SMD disks, even the Ampex, at either Masscomp or Stellar.
Truth is by then we had started to concentrate on ESDI 5.25" FF disks from the 19" and 8" SMD technologies (using a cheap SCSI to ESDI controller). But it was a little of "you get what you pay for" problem. The new controllers for the smaller disks cost a lot less (Xylogic VME/Multibus vs. SMS SCSI); so we were starting over with the SMS folks to educate them. Apollo had been SMS's primary partner (did you ever wonder why they supported at 1056 byte block as one of their native block sizes), but to the SMS's folks credit they picked up the ideas of good error recovery reasonable fast.
Clem
PS The thing I fear lost to history was PC's code for the Masscomp formatter/tester/exerciser for the 45x Series. It was an amazing piece of work. I think we still have the OS sources kicking around, but the diagnostic system was of less interest I fear.