Tech Tool Pro doesn't really do much of anything useful that you can't already do without it. Here's the "feature" list on their site, and why you don't need any of them.
Internet Speed: There are many web sites that will speed test your Internet connection for free.
Mac Drive Testing and Repair: That's one of the things Disk Utility does.
Emergency Startup Disk: Disk Utility can create a clone startup disk.
Protect Important Data: Okay, slightly useful. If you empty the trash, TTP redirects the contents of the trash to a hidden folder. In other words, the data is never actually deleted. Nice if you don't mind watching your drive's space slowly fill to the brim with "deleted" files that are still on the drive. The simple trick though to avoid the need for such an app is the same as your real trash can at home. If it isn't trash, don't put it in the trash to start with.
Take It With You: So you can punish someone else's Mac?
Complete Hardware Testing: Each Mac has its own built-in hardware test. Restart and hold down the D key.
Advanced Memory Testing: Again. Restart with the D key. RAM is also far more reliable that a decade or more ago. The chances you will ever have a bad stick to even find errors on are very low.
Take control of your Mac: The Mac will clean reports and other aspects of the Mac itself. Rebuilding system caches isn't something that needs to be done on any type of schedule.
Diagnostics and Repair: And we're back to restart with the D key. If there is a rare issue with RAM, the only repair possible is to replace it. If disk errors are found, run Disk Utility.
The surface scan part of it (for rotating hard drives) is already done automatically and continuously by the drive's own firmware. If bad blocks are found, the drive automatically moves the data on those areas to good blocks and maps out the bad ones so they can't be used anymore.
Video memory? Same as their RAM test, since video memory is RAM (a faster type). And the result is the same. If there is a problem, you can't fix it. You replace it.
File optimization (also normally referred to as defragmentation). For SSDs, you never, ever do this. EVER! You will only succeed in wearing out the drive faster. It doesn't matter how fragmented a file is on an SSD since every cell will read just as fast as it would if the pieces of data being read were all adjacent to each other. For hard drives, the OS will automatically defrag files above a certain size if they need it. Bottom line, you don't need to do this manually at any time.
Protection Preferences: If you want to grossly slow your Mac down and have TTP use up gobs of drive space, this "feature" is the way to do it.
