In August 1999 I was using the Atlas 10K, which was the best at that time. I received the 18LP sometime in the spring of 2000, and then of course the X15 was vastly superior to any 10K drive at the time. Back then many of us ordered SCSI drives from Hyper Microsystems which had the new models in stock fairly early and was a SR sponsor.
IIRC I was using the 28 GB Barracuda in late 1999. They were hot and noisy, but fast for ATA at the time. The 27GB Maxtor DiamondMax Plus 6880 was probably a bit better, but I opted for the BIOS-busting Maxtor DiamondMax 36/40 5400 RPM capacity drive around that time.
The WD raptor was an SATA drive from the start, but a 21st century product. It was neither fish nor fowl, having low capacity compared to 7200 RPM ATA drives and mediocre performance compared to 15K SCSI drives. However, it was cheap and popular with the gamer types. I still have that clear window version purchased more out of curiosity than for any other reason.