Other than the aforementioned problem with an NEC 2x scsi drive and PlayCD (incompatibility is mentioned btw in the AmiCDFS documentation), I've never had a problem with installing a 50-pin scsi cdrom drive to gvp, A2091 or other controllers. I've used AsimCDFSv3.10, AmiCDFS and the built-in scsi cd support with OS3.9. Not to say anything bad about Asimware (great software, btw) but the only cd problems I've had are with ide drives using the Asimware atapi.device on an A4000. I recommend using IDEfix97 and AmiCDFS for better atapi compatibility, but that's just my experience.
