I know on PCs you had stuff like Diskeeper etc.. to do the occasional drive defrag to recover speed and concatenate the free space etc.. Does OSX require such a utility?

I've recently had an exchange with people who scoffed at it and sneered that it doesn't work or doesn't work well. Any counter-opinions? What other OSes or distributions use that code or similar code?

Most modern Windows operating systems will defrag your computer automatically, but you can do it manually if you have Windows 7, 8, 10, or Vista.