A load of crap!
"They can cause problems such as data loss, greater degrees of fragmentation and even wreck Windows system files."
Utter bull$#*!! It is close to impossible to corrupt the file system or files as all free and commercial defrag software that I am aware of use the Windows defrag API. The Windows included defragger, freeware, commercial defraggers all do. They are all equally safe or unsafe.
Top Ten Reviews is a jack of all trades. They lack specialized knowledge to review specific software.
"Another problem with freeware defragmenter programs is their lack of support for many current technologies. Solid state drives are one example."
More BS. A SSD should never be defragged. Defragmentation software writers, specially the commercial ones just came up with 'SSD aware defrag' to prevent they became obsolete. It is just snake oil. Your SSD does not need defrag.