I have both of these drives, a Cheetah X15 and a WD 1800JB. My Cheetah has WinXP, and I use the WD for my programs. However, I bought a Adaptec 19160 (Ultra160) controller so I could get the max performance.
1. This generation Cheetah is very loud, and has a constant click sound, which is normal.
2. SCSI feels a little more responsive, but not too impressive to me. Meaning, if my Cheetah is loading something which takes a 30 seconds, I can open up Outlook Express or Internet Explorer and not have to wait a long time for it to come up. But, it isn't amazingly responsive.
3. When copying a file to itself, the Cheetah is takes aprox. twice as long! The same goes for unzipping/unraring a large file. This is the WinXP bug I guess and miserable write speed. To me, this is real-world stuff (maybe not the copying), and the SCSI drive is jus dismal, and happens to be rather common task.
4. Tranfer Rates (winbecnh99) however on both drives shows the Cheetah starts at 60 MB/sec and can sustain that fairly well. The WD drive starts at 50 MB/sec and has a sharper drop as the test progresses. So I'm confused why I get a much better transfer rate through this benchmark for the SCSI drive.
I'm planning on installing either XP and/or Windows2000 and boot off of my WD drive and see how the system feels. For all I know, the SCSI drive is performing very well for OS functions and maybe I have a more responsive system than I realize because I'm just use to running off of a SCSI drive.
If you want to run XP, and you wanna buy now and not wait a couple months for MS to release some kind of "fix", I'd say get one of the new IDE drives with the 8 MB cache. They seem very good, and you gotta love that massive storage!