I prefer Diskeeper, with a much older version being the basis of Windows' defragmenter. Diskeeper's marketing dept claims it is better than PerfectDisk. Of course, PerfeckDisk's marketing dept claims it is better than Diskeeper. There are no conclusive results from independent, unbiased third parties so it is hard to tell which is correct. Regardless, most would agree there isn't a significant difference, so either one would be sufficient. Just do not defragment excessively, as that can wear out a hard drive.
Hope this helps,
I have Auslogics Boost Speed. I downloaded the trial version of PerfectDisk. After I run PerfectDisk, if I check BoostSpeed it tells me my disk needs defragmentaion. My computer seems to be faster after using Perfect Disk. Is there a defragmentaion program that is better than these two?