I've tried Speed Disk with my SystemWorks 2k3 and I've tried O&O defrag, diskkeeper 7, and Perfect Disk.
PERFECT DISK 5.0 is the best!! It takes less time and compacts files more effectively. I defrag at least once a day. And I usually run it through twice. My suggestion to Perfect Disk (GHayes) would be to have an option to defrag more then one time through, or make the first "swipe" more effective.. Any of you other guys defrag more then once to tighten up your files..??
PERFECT DISK 5.0