Defragmentation is one of the chores of computer ownership, something that's tedious but which has to be done regularly. Windows includes a free defragmentation tool, but there are plenty of competing products. How do you compete with "free"? You make something worth paying for. PerfectDisk 11 ($40, 30-day free trial) is that worthy tool.
PerfectDisk 11 has one of the best blends of features and usability I have seen. A number of other defragmentation programs have as many options, but they tend to be hidden in obscure dialogs, or worse, require you to edit script files. PerfectDisk 11 is built to modern interface standards: Everything can be clicked on or off, and the dialogs I saw were clear about what options meant. Furthermore, most settings have a "Help" button clearly placed nearby.
Aside from simple ease of use, PerfectDisk 11 has several other stand-out features. One is boot time defragmentation, which allows PerfectDisk 11 to defragment system files normally locked during use. (PerfectDisk 11 also has the capacity to take a drive offline during runtime and defragment it; this feature should be used with caution.)
Another very nice feature, one which is usually found only in applications dedicated to this purpose, is a duplicate file finder. PerfectDisk 11 will scour your disk for identical versions of files by matching actual data contents, not just names. You can then examine the list to delete redundant files. This function could use a few more bells and whistles, especially when it comes to sorting through long lists of duplicates (I had a few thousand), but since it's a side feature, not the main focus of the application, it's certainly adequate.
PerfectDisk 11 also allows for the creation of customized optimization schemes, to let you maximize free space, access time for frequently used files, and so on. It also has a decent set of disk analysis tools, showing the breakdown of file types, frequency of use, and degree of fragmentation.
This review covers the "Professional" edition. A slightly less expensive "Home Premium" edition is also available, which lacks the duplicate file finder and some of the defragmentation customization options. Given the range of features and ease of use, it's well worth upgrading from a free product to PerfectDisk Professional.