Nobody needs to spend £20 on a disk defragmenter, let alone a glorified registry cleaner. Fragmentation just doesn't slow down a modern home PC very much until it reaches high levels. I'd be extremely surprised if you could notice any performance difference after using PerfectDisk compared to a decent free program like Defraggler, or even the built-in Windows defrag. Lots of free programs will even do the 'advanced' stuff like boot file optimisation.
As for PerfectSpeed... like all registry cleaners, it's snake oil. It's very hard for these programs to identify which registry keys can be removed, apart from a few very obvious ones. And at any rate, modern (post-XP) versions of Windows don't seem to be particularly susceptible to registry-related slowdowns. I'd be pretty surprised if you could notice an improvement after using that, too.
It certainly doesn't do anything else useful. It deletes your temp files - which CCleaner will do for free. It clears your history - which CCleaner will also do for free. And it'll change a few settings for you - which you can do for nothing.