Have never tried it, although I dont have any defragmentation software right now in my machine, I must say that I only use the one that comes with Windows. I think its okay, although I agree that it is definetely not the best out there. If you want a defragmentation program that would take you years for it to finish in a big HD, try Norton's Speed Disk!

Its so slow that I can leave it the whole day with a HD that hasnt been defragged for months! And I really dont see any big difference from its results than from the results from MS defragger! (BTW, Windows 98 defragmenter was also very slow)
dan